Keep in mind that the 7D pixel pitch is 4.3 microns wide on a 0.5 micron process.
I've said it before but I'll repeat that:
if we see Canon increase the MP on their new APS-C cameras, the process CD will HAVE to be smaller (hopefully the newer 180nm process).
Having said that, all the rumors point towards a 20+MP camera which is definitely an encouraging sign.
excuse my ignorance - but what will the 180nm process help?
i thought that the larger photodiode (up to a point) helped make a cleaner picture (i am sure that my understanding is simplistic...so please help me understand!)