I think the days of any start-up (new) gaming site raising thousands of BTC in bankroll funds is effectively over. It really is all about the reputation of the owners but even so since each BTC is worth a huge amount investors will find great difficult in parting with their funds.
It also makes me kind of think that privately funded bankrolls are almost silly. If you can get your whole bankroll paid for, and be paying only like ~15% commission .... almost seems silly to not do that.
If you can get away with it, that is. Which won't be the case with most people starting their own site if they don't have a very high reputation/social proof/etc.