Richard, if a 7d replacement could give us what the 7d promised but couldn't quite deliver, a lot of people would buy one!
If you have a few minutes to spare, you could read this.........
http://wp.me/p2BFlt-dg
I don't know where these rumours come from but this one could easily mean that the announcement of a 7d replacement is imminent but that it won't be called a "7d mark 2"
Thanks for that Jerry

I don't think the market demand for a 7D Mk2 is in doubt, the question for me is rather if it now suits Canon to make one, with the features we want at a nice 7D-like price point. Frankly, I don't think that was ever going to happen and Canon was always going to push it higher, but with the new shape of the market, that may be worse than we know, I fear that every manufacturer will have to reconfigure their plans quite radically.
On your blog link, I'm not sure any crop-format APS-C camera will achieve what you (we all) would like. I don't think Canon will push the pixel count much on a new 7D, as that's already adequate IMHO and any more will slow the potential frame-rate. But if they can improve the ISO performance by one stop, that will be quite an achievement.
The other problem is simply lenses don't perform as well on smaller formats. I don't know how familiar you are with lens MTF sharpness performance, but from my numerous magazine tests I know that on average MTF level drops by about 12% just by changing from FF to APS-C. That is very noticeable, and an unavoidable fact of physics, regardless of the sensor or pixels or ISO performance.
The only way to compensate (partly) for that is to start with an extremely sharp lens in the first place, one with resolution 'in reserve' and can take that hit better, like the Great White Canons - they're just in a different league. 400/5.6L is a fine lens, but it's not in the top class, and the extender only makes things worse. Better still, switch to full-frame and an even longer lens to get the reach back - short answer, 5D3 and 600/4L. There's no avoiding the fact that high quality long lens work is very expensive, and no new camera is going to change that.
Suggest hire say a 600/4L or 500/4L, and shoot the 7D side by side with your 400/5.6L and extender. And also, watch out for poor atmospherics messing things up.