Bill Scherer , Nov 03, 2008; 09:45 p.m.
I've got one of the $20 dollar ones. No focus confirm of course, but it's solid and dependable. Perhaps over priced, but the quality is good. It was from kawaphoto on ebay.
As for the focus confirm adapters, I've never tried one. I can't even figure out how they could work. If anyone knows, I'd love to hear it.