Conurus is working on an adapter that will allow Canon aperture control - it won't be cheap.
Other lenses with manual aperture control can be used manually (Canon is electronic only)
It's highly unlikely that there will ever be an AF adapter for anything other than the Sony/Minolta lenses. However, with the NEX-7's Focus Peaking, using manual focus should not be that bad.
I can imagine someone with a special requirement wanting to use a Canon or other lens with the NEX-7, but having a bunch of Canon lenses, i can't think of a good reason why i would use any of them on a NEX-7
if you're really interested in lenses that will work with the NEX-7, a subscription to diglloyd Advanced Photograpy is well worthwhile - there are a number of optical compatibility issues adapting lenses to the NEX-7