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.
They have enough bank to cover payouts hence they dont require any investors to support the site. Just-dice would be a good place to invest imo but it's in clam though.