Even if the idea were to be successfully implemented and managed- while you might save on bandwidth, it would be at the cost of a great risk. That risk is presented in two forms:
A) If you are giving away large enough videos to need to be seeded in a torrent, you are giving away more free porn than is productive for making money. The members simply will blow their wad many times long before they think about signing up.
-- Perhaps, however, you would like to be poor and a savior to the surfers. With that goal in mind you could purchase tons of content and share it with the masses...
B) If you are attempting to attract the torrent crowd, you are attracting the type of people that want to steal content. There are very few exceptions to this, the people that are looking for legal torrents- not many. So the risk here is that the only signups you'll get will be people who want to rip the site and upload the content to "real" torrent sites.
I doubt the idea would be successful. If I were a program owner I would not allow it for reason B.
But... I praise you for thinking outside the box, and for striving to remain honest and legal.
