While not a scam per say, this one drives me nuts.
Keeping an eye out for a 64bit Expansion Chassis. There's a guy who is flooding ebay with chassis saying they are HD compatible, yet they are really only the old 32bit versions. He won't post the actual model numbers, just that they are HD compatible, which they aren't. And he is selling them at about the prices they would cost new.
Just seems pretty dishonest to me.