As it is right now, I can't see this really succeeding in a major way. Youtube's popularity is based on the fact that it's fast, reliable, and free. Movie rentals are one thing. But taking the biggest aspect of Youtube and attempting to charge for it will only turn most people off.
The Young Turk's paid channel is a good example of doing this wrong, I think. It's basically them throwing up a bunch of footage of them screwing around before and after shooting.
And it seems like each Youtuber can pick their price? So people could potentially find themselves subscribed to a dozen pay channels at varying prices? It sounds like a recipe for disaster to me. I think this is destined to unravel for Google or never pick up ground at all.