Regan Nursery is the only place I know that sells them bare root and grows them out in 5-gallon containers. We looked into the possibility of a co-op once and found that wholesale orders have to be huge, so huge that a small or even medium-sized nursery might not have the customer demand to make the order worthwhile. As I recall, you had to buy the full line too, and most people have never heard of most of the roses and wouldn't take a chance on them. If they only knew how wonderful they are, though, people would snap them up.
How could anyone resist Hot Romance, for example?