Like some other responses, I'm not sure a camera upgrade is the best thing for you, but in case you are determined to do that, here are some considerations.
Your first decision will be whether to stick with a crop camera or make the switch to full frame....
If wildlife is one of your favorite subjects, expecially small wildlife such as many birds.... Then a 6D, 5DII or other full frame camera most likely is not your best choice. The crop sensor cameras are generally better for that purpose. The new AF system in the 6D is an unknown at this point (more points than the 5DII, but like that camera only the center one is the better cross type). The 5DII is not up to stopping action as well as the crop cameras can. Among the full frame models, only the 5DIII, which sounds to be more than you want to spend, offers AF that can be relied upon for faster moving situations. (Again, 6D is supposed to be better than 5DII, but I'm skeptical until I see some feedback from actual users.)
Unfortunately, it's just the opposite for landscape photography... to some extent. Usually a full frame camera that captures the maximum possible fine detail is desirable. However, what you do with your images is also important. To really make best use of a full frame landscape shot, you'd have to make large prints from it. Web resolutions and for smaller prints, up to about 16x20", you won't see a lot of advantage from the FF camera.
Another advantage of crop cameras is that your lens kit can be smaller, lighter and less expensive. Crop cameras can use all the available lenses, both the EF and the EF-S/crop only. Full frame can only use full frame lenses. And, to get the same reach, particularly with telephotos, you are looking at a bigger, heavier and more expensive lens for full frame. For example, I use a 300/4 IS a lot on my crop cameras, easily handheld and portable. If I want the same reach with my 5DII, I need to get out the 500/4 IS and a tripod to put it on. Or at least a monopod. 6X the cost for the lens alone, way bigger and lots heavier.
So, first decide which you need... full frame or crop. I think it will come down to your subject priorities... if it's Wildlife, especially smaller subjects, you will probably want to stick with a cropper. If the priority were landscapes, then the full frame would probably be a better choice.
If you decide to stick with crop cameras, you're down to two choices.
50D > 60D.... You'd be getting about one stop higher usable ISO, video, articulated LCD screen, lighter weight, minimal difference in overall image quality, slightly higher resolution (18MP vs 15MP). No significant change in AF performance. You'd be giving up Micro Focus Adjust feature, getting a slower top frame rate and more plastic construction, and some of the controls of the 60D are laid out differently.
50D > 7D... Very similar IQ and ISO performance to 60D (one stop higher ISO than 50D & minimal difference in overall IQ, slightly higher resolution). Faster and fancier AF. Heavier weight. 100% viewfinder.
Actually you have a third choice.... Stick with your 50D and put your money into lenses instead. Frankly, if I were you that's what I'd do.... Unless you really, really need video, or the AF performance of 7D, and/or the add'l stop of usable high ISO that either 60D or 7D would give you.
Some lens upgrades would make a much, much bigger difference in your images, than changing cameras will. And your 50D is still quite capable. You'd only see marginal gains with a newer model.
If you stick with crop cameras, consider getting a Canon 10-22 or Tokina 12-24 for those landscape shots. For the mid range, a Canon 17-55/2.8 would be a great upgrade over your kit lens. A single lens that might serve both purposes and is very compact, consider the EF-S 15-85mm IS. It's not quite as wide and not an f2.8 lens, but the 15-85 delivers top image quality... and still is compact, with fast USM and IS. You're pretty well set with your 100-400, unless you feel the need for even more reach (Sigma 150-500 OS?).
As to the macro lens... again you have a lot of possibilities. Canon makes a number of very good ones, and when it comes image quality, there are many excellent third party options, too. It comes down to features of the lenses that best meet your needs.
IQ aside (it's not a concern, they are all good), size is an important factor. How big and heavy a lens are you willing to tuck in your camera bag for occasional macro shooting. If you want a more compact lens and plan to stick with a crop camera, Canon offers the 50/2.5 "Compact" macro, but I'd recommend 60mm to have a little more working distance and because the Canon 50mm macro isn't a USM lens and isn't 1:1 capable without additional accessories. Canon EF-S 60mm macro is excellent and can do full 1:1. And Tamron offers a 60/2 1:1 macro, which ia a full stop faster aperture than any other macro lens and can double nicely for portraiture, but gives up some focus speed to the Canon USM lenses. In either case 60mm still puts you a little close to some subjects, but is a bit smaller and easier to tuck into a camera bag. Sigma offers 50/2.8 and 70/2.8 macro lenses, both 1:1 lenses.
Personally I prefer a 90mm to 105mm focal length, on crop cameras. This gives more working distance, often useful for certain subjects. And it's not so long that it's hard to get a steady shot... To get enough depth of field with a longer lens, it's often necessary to stop down quite a bit and that leads to slower shutter speeds.
In this range, it's hard to go wrong with either of the Canon 100mm lenses. Personally I see little need for IS on a macro lens, so I use the non-L, non-IS 100mm. There is also the Tamron 90/2.8, an excellent model that's been around since the days of film and manual focus and has just kept getting better over the years. Tokina offers a 100/2.8. And Sigma offers a 105/2.8 OS (and just recently discontinued a non-OS version). All are excellent optically, but differ in features and price.
Other things to look for in macro lenses....
Tripod mounting options. Both the Canon 100mm lenses can optionally be fitted with a tripod mounting ring, which is very convenient and handy (most of the third party macros around this range do not provide means of fitting a t'pod ring). The Canon t'pod rings are rather pricey... but there are considerably cheaper third party clones on eBay and elsewhere that might serve. (Shorter focal lengths are small enough that a t'pod ring is less necessary and most longer focal lengths come with a t'pod ring.) AFAIK, none of the third party lenses in the 90 to 105mm focal length range can be fitted with tripod mounting rings.
Focus speed: The Canon 60mm and both the 100s are USM lenses. Because a macro lens has to move it's focusing group a long, long way, they can be slow focusing. Some third party lenses have similar (Sigma HSM), but most don't (I don't think Tamron has put their new and similar USD on a macro lens yet).
Internal focusing design of the Canon 100s is another factor... makes for a bigger lens to start with, but they don't change length when focusing. Some macro lenses double or triple in size, when focused to their closest. This can effect working distance and balance. Likely it also effects focus speed to some degree. An IF lens might be a little faster focusing. On the other hand, an IF lens design effectively changes focal length as it's focused closer. The Canon 100mm lenses end up about effective 70mm at their closest, 1:1 magnification setting.
A focus limiter is another nice feature, mostly pertaining to focus speed. The Canon 100/2.8 USM (non-L/IS) has a two step limiter. The more expensive 100L has a three step limiter. Some third party lenses have a limiter, others don't. I should note, a lot of macro shooting is done with manual focus... it's just easier at higher magnifications. So focus speed might be more of a consideration for secondary usages of the lens... such as portraiture or any other short telephoto purpose.
Have fun shopping!