I didn't know people were allowed to breed mixed breeds on purpose I guess you learn something new everyday I would LOVE to have another Toller/border collie but I wouldn't breed them. I think they make an excellent breed for a couple reasons:
1)they are great retrievers
2)they are soooo smart
3)they are very eager to please
4)they are very good at herding
I think too many people breed all the mentioned breeds, they are more popular than Labradors and Goldens in my City!