I wanted to suggest Primedice because it is the most trustworthy dice site at the moment, but according to
http://dicesites.com/ they have
no invest option. Tha's strange IMO. How this can be that you don't need investors? I thought it works this way: the more investors you have the better.
Maybe I'm missing something in understanding economy.
The larger the bankroll, the larger the bet you can take and hence the more business you can do. But at the same time, taking investment will dilute their shares on the site profit. There are some other issues as explained by Stunna himself in
https://bitcointalk.org/index.php?topic=208986.msg11585762#msg11585762.