Usually these rental companies do have some gems..I remember I used to rent imports from RedOctane and when they were adding next gen stuff, they offered me a disc I had on rental as a "special purchase"
I sent it back because I didn't think the price was worth a disc/manual only copy.
However, I have heard of a guy who had an empty game case, rented a Suikoden II, filled is case, and paid the $49.99 for the lost item..
It's "legitimate" but I still think it smells of fraud, I like making money but would never go that low
On topic: do these DDR games come in box or just loose pad and game?