It wouldn't be a bad idea to think about IndieGoGo or KickStarter, but I do understand not wanting a time constraint, do you -have- to put a time constraint on it? Couldn't you do something where the little extra things you offer could be... I dunno something that's not necessarily game related? For example http://www.indiegogo.com/projects/ithaka-of-the-clouds?c=activity a couple of indie game designers that I really have fallen in love with along with their composer have an IndieGoGo right now and they have a pretty neat little listing of what you get and whatnot involved with the funding. Check out what their doing and consult each other! :) Cheers!