I'd be voting for a 650D, same 18MP sensor, maybe a digic5 to make upgrading worthwhile. I don't think there's anyone I know who's "upgraded" from a 550 to 600, but seeing as canon call the shots they can just discontinue the 550D, and then users upgrading from P&S or 1000D can choose the 600/650.
7D2 will almost definitely hve a new sensor, what it is i don't know. Either 18MP with a lot higher IQ than currently (larger pixels a la 1dx), or the same IQ-per-pixel as the current 7D with more of them (keeping pixel-size the same and fitting more in the same space). If it's 24mp or more current-7D-owners might upgrade, but either option would be a nice upgrade for 60D/xxxD-owners. Keep the rest of the features the same, there's nothing wrong with it.
I still think that there'll be another wildlifing body out to replace the 1D4, whether it's what the 1D5 should have been (18-21mp aps-h, same af, same body, 8-10fps), or it could be a high-mp aps-c (21-30, same af, same body, 8-10fps) for somewhere between 5D2 and 1D4 price.
But not yet, feb will be a 650D. (if there's a lens, please please please EFs 35/1.4)