If I were you Ben I might be tempted to try out the D700 for a while, just to give Nikon a spin, but I'm not sure I'd want to deal with the hassle of switching out all of my lenses; it would be tempting though.
Do you really think you'd be happy with a 1DsII? You'd have to deal with the size and weight of a 1 series again and you say you don't really need 1 series AF. That would mean the only advantage over another 5D mkII would be the weather sealing and for me that wouldn't be enough of a reason to give up the 5D ergonomics, high ISO performance, LCD, etc.
5D "classic" and 1dmkII - As you say, the weather sealing wouldn't do you much good as the 1d wouldn't even be your landscape camera. This option would only make sense to me if you shoot alot of sports/action.
A900 would be too much of a stretch for me.
I do think if I were you I'd wait until Sept 1 to see what Canon announces, but I'm doubtful that it will be a FF camera, unless the 1dmkIV goes FF.
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@ duct tape. If you can't duck it, **** it!

