Booking an entire cruise ship requires large deposits. It's going to require someone with some deep pockets to get this going. The other issue is financial risk. If you book the entire ship and don't sell all the cabins you not only loose the money you paid for the cabin but you also have to cover the losses cruise line expects to make from gambling, drinks, restaurants, and diamonds. There are lots of people who will say they want to go, far fewer send the check. Its not easy to fill 2,000- 5,000 cabins. Cruise ships also come with a lot of rules. We've been on several clothing optional lifestyle cruises. Any sex in public would likely get you thrown off the ship anywhere it happens to be, and their will be restrictions on nudity. It would be far easier to book the group into Hedonism. There is no risk. It's clothing optional, and has a sexual orientation. Then when you outgrow Hedo you can move to a cruise ship.
Don't know about anyone else, but I would be just fine with 100 black guys and 10 couples!