First off, wow, love all the technical data, but, much of it is a bit over my head. I read and do my best to understand though.
As to the perfect combo, as with everything it really depends on what your shooting. Right now I'm riding the 5d3/7d combo, but find that the 7d more often than not just sits to the sidelines. I am mostly shooting weddings, portraits and events though. Lots of lighting conditions, from well lit to fairly unlit - and more times than not in tight spaces. Even shooting concert from the soundboard I have found that the mk3 with 70-200 and no TC is fine (especially because on the mk3 I have much more room to play with ISO, which means I'm not as limited in DOF options, where with the 7d I'd want to stay as close to 2.8 as possible. But, given that I am usually shooting from right in front of the stage (i get soundboard shoots like 2-3 times a year), investing in a better way to cover that range just doesn't make sense (also, I'm not shooting sports all too often).
For my purposes, the best combo for me would actually be the 5d3/5d3 combo. But I'd also like to pick up a 16-35 this spring too. I have the 10-22, and I have been enjoying using the 7d-10-22 partnered with the 5d3-70-200. At a wedding that gives me close intimate shots, and Wider fun shots. But yeah, I am pushing the ISO on the 7d higher than I'd like in that situation.
Other options are snagging a 5d2, or, possibly a 6d when we find out more about how that body works (I kind of like this option mostly because if I went this direction I could potentially keep the 7d, if i went mk3 I would have to sell the 7d (unless I can book more than I am expecting to book this fall). I have also been giving a good look at the 1d4 too.
All that said, my perfect body combo is probably not the same as everyones. It all depends on what you shoot. If I were offered a big contract to shoot sports this year, yeah, I'd be re-evaluating my setup big time. But as it stands for me, the advantages of FF outweigh 1.6 crop.