Where do I start in Creating a Site for people to upload their Videos and the Public can buy the Vid

Had a Friend Come up to me and Ask I would Like to create a Site that users Register can upload their videos on to my site and be able to sell them.
The first thing that came to mind is Worppress and Marketpress. I have used marketpress before and was wondering has it improved in the last 10 months?
Also does Marketpress Have ccbill payment options or Can it be added? has anyone added it?
Yes this will be an Adult Website and ccBill allows Adults site unlike Paypal.
If you can think of other plugins/ themes that can get the same results. Or even a Full blown Plug in from here or outside of wpmuDEV that would be great. it doesnt have to be that the sellers have a site One site with sellers selling on it would be great.

The main features that we need is
1. Payment to the Site owner to Use the Site on first signup and as an option to turn on or Off at Site owners Will. Probably will be off at first
2. Split Payments for Website owner and Seller to go to ccBill
3. Easy interface for Models to upload their Videos. bear in mind they never used wordpress so Front side image upload and Description Would be best.

If there is any other features we need I will post them.