Reversed 50mm? 500D? Separate Lens? Too many options!!

I love macro photography but I don't yet have much macro ability with my DSLR setup:
30D
17-50mm f/2.8
EF 70-200mm f/4 USM L
Sigma 10-20mm

I have decided to order the following:
Canon's EF 100-400 f/4.5-5.6 IS L USM lens
Either a 430EX or 580EXII Flash

On top of that order I'd like to add equipment to allow macro photography. I'm thinking about a reversed 50mm lens to the end of my 100-400mm (Thanks to Alex Paul for giving me the idea, though we discussed using the 70-200mm instead, I think the new 100-400 is likely going to get more use once I buy it). This would be cheap and wouldn't add too much weight.

The other lightweight option is canon's 500D close-up filter used on the 100-400mm.

Finally, I could spend a lot more money and get a dedicated macro lens, but I know I would not bring it around with me as much due to the additional weight... but I love image quality over everything...

So my question then is: What option gives better IQ? My guess is: 1. dedicated macro lens, 2. reversed 50mm, 3. 500D. How much quality is sacrificed by going with one of the lighter/cheaper options?

Any recommendations/sample​s would be greatly appreciated!

Triptoph wrote in post #3807026
This would be cheap and wouldn't add too much weight.

Meaning no offense, but how can you be concerned about the weight of a macro lens if you are going to be lugging around the 100-400mm?! It weighs 1.38 kilos. In comparison the 100mm macro weighs .6 kilos and the EF-S 60mm weighs .33 kilos...

Triptoph wrote in post #3807026
So my question then is: What option gives better IQ? My guess is: 1. dedicated macro lens, 2. reversed 50mm, 3. 500D. How much quality is sacrificed by going with one of the lighter/cheaper options?

Any recommendations/sample​s would be greatly appreciated!

I would say the macro lens then the diopter and then the reversed 50mm. You'd be amazed at how sharp Canon's 500D diopter is...

I would go for a dedicated macro lens and a diopter for the 100-400mm. At it's closest focusing point the telephoto won't be sharp without a diopter, and if you really want to get into macro a dedicated macro lens is a lot easier to use that a reversed lens...

Dalantech wrote in post #3807240
how can you be concerned about the weight of a macro lens if you are going to be lugging around the 100-400mm?! It weighs 1.38 kilos.

Ah well, it all adds up. If there were a lighter option for a high IQ 400mm telephoto lens I'd certainly be interested. Since it's already so heavy I'm trying not to add more weight unnecessarily. I just don't know by how much the IQ differs between all these options.

Dalantech wrote in post #3807240
I would say the macro lens then the diopter and then the reversed 50mm. You'd be amazed at how sharp Canon's 500D diopter is...

Thanks... anybody happen to know of any good examples of the 100-400 + the 500D?