I run 32 CCBill paysites (with more to come) so the cost of doing a paysite is:
CCBill registration fee ($1000)
hosting
domain
web design ($500-$2000+ depending)
content (either bought or you shoot it yourself)
Affiliate Program setup/scripting (costs vary)
If you're editing video and uploading to tubes yourself or hiring someone to do that for you. This includes any 'affiliate' work like submitting galleries, free sites, etc.
So if you have enough decent content and a budget then it's worth taking a shot. But since you're not sure if this niche will sell or not I would actually try opening a clips4sale store first and test out the content/concept there first.
If you're into the niche then you might have a chance if you're passionate about it, and creative in your presentation/execution. But the paysite game is a tough one these days.
Good luck!!