What I think you are asking for is sponsor programs that have a product that can be co-branded. Usually this is available with something that is a product, like an adult store, live cam, software, penis pills/herbals, possibly a payperview theatre, or even an adult personals site.
I don't think you'll find a sponsor program that has a co-brand though for a members only niche type porn site.
PE Cash has a brandable adult store program
Top Bucks has like 5 or 6 software items that you could literally take and build a site for and then just link to their respective buy page with your id coded link. Either do all items on one site, or do a site for each product.
Mens Niche has several products that are available as a feeder page - easy to build a site and do an include to bring them into the site. The code they provide would carry your id and you'd get a % of any sales.
Adult Friend Finder has a number of personals websites that can be co-branded. Note: you need to register for EACH one you'd want to promote - this isn't a site where one account lets you promote all of their sites.
This is just some I can think of off the top of my head. Hopefully some others on the board will stop by and ad on any others they know of that offer a co-brand program.
Good Luck