It will be great to see a 7D with APS-H sensor for the following reason:
1.The size of the body can be smaller than a FF body (compared to 5D II).
2. with the same MP, it will have lower pixel density than the APS-C and hence better low light performance and better dynamic range.
3. With 17-40mm lense, it will give us a 22mm equilvalent focal length. at the same time to avoid the bad optical result at the corner when used on FF.
4. The price will between the 7D and The 5DII (hopefully)