@moreorless : now this is going to make choices really interesting. I can see current 5D2 users wanting to jump to "your" 3D and first-time-FF users taking your 5D3 prediction. I consider this very business oriented and logical
My feeling is that an entry level FF body would really be the way to gain an advanatge, Canon, Nikon and Sony have all seen that high megapixels in a smaller body sells with the 5D mk2 and I'd be supprized if they didnt go after that market this time around. The smarter business move would I'd say be to realise that the strong sales of the 5D mk2 at a lower price point have hilighted theres a market for a $2000ish FF body. If big megapixel bodies are all we see with the lower end FF market this time round there launch prices are likely to be $3000+ which could price many potential buyers out.
That could actually be more important than who gets the very best spec high megapixel body, if say Canon only has 32 MP and lesser AF than Nikon are many current 5D mk2 users going to switch? probabley not with the investment in lenses. The more important battleground would be getting users locked into a system and if Canon are the only people with an entry level body thats a definate advanatge to them since crop upgrades cannot be depended on with many users having to sell EF-S/DX lenses anyway.