My two cents on this. The 7D is really a little bit odd; if one digit (xD) canons are for the pros, then the 7D was a bit weak. On the other hand there are are 3 consumer bodies (xxxxD, xxxD, xxD). This lineup somehow makes sense, just that the 7D is not really pro-grade.
This is how I see the future lineup from Canon: The 1Dx is for sport and wildlife shooters (high speed with 12fps, high ISO up to 200k). Then there will be the 5DmkIII, it looks at the moment that it won't compete with the D800, but I can see where it could be placed. the 5D will be for photojournalists who also like to make movies. The 5D is smaller more mobile package then the 1D, emphasis will be on good high ISO (low light ability, and video)
But there is somethin missing in the pro sector, and this is the landscape shooters. And here could the often rumored 3D fit in, which will be aimed at the D800. A camera with high resolution (40+MP) but a slower speed.
With these 3 pro bodies, there is no room for a 7D, so the xxD will move up a little (to where the 50D was). The difference between a 600D and 60D is quite narrow at the moment, and I think it makes sense to widen this gap.
Conclusion: 3 consumer bodies (entry, standard, advanced) and 3 pro bodies (Action, Landscape, Photojournalist) from canon, this would be a nice and logic lineup.