I've bought a couple refurbished cameras.
They only came with 3-month warranties. One was a professional Canon model (EOS 1D) and the other a high-end Olympus. I'd be suspicious of claims of a full-year manufacturer's warranty.
Mine both were in new condition and I never had any problems with either one. One was purchased through eBay and the other... I think it was Cameta Camera. I've also bought a couple refurbished negative scanners that were like new.
I've only heard of one complaint about refurbished cameras, and it apparently was scuffed and scratched pretty badly. I don't know how you'd insure that wouldn't happen, but it must be pretty rare. It was an Olympus, and I think I read about it a couple years ago.