Unbound.co.uk lets you pledge money to help fund a book. Patronage is nothing new of course. A pledge of the smallest amount - mostly £10 - gets you a copy of an ebook version and your name printed in it. Higher amounts get you different things, like paper editions, invites to a launch party and so on.
You also get access to the author's "shed". I gave £10 for Robert Llewellyn's book News From Gardenia. He's the guy from Scrapheap Challenge. I hoped to hear about the writing process, but he never put much in his shed, and I got the impression that the book was mostly completed anyway, and just needed money to publish. (Not that the process of publishing is trivial.)
I don't think I'll be pledging again. £10 is a lot for an ebook with your name in it. It's a good idea though, if you're an author who can get lots of fans and you can't convince publisher's that your book will do well. It's good too if an author you like shares good stuff in their shed.
Unglue.it takes existing books and pays the author or publisher money to produce an ebook with a Creative Commons license. The first one that's had it's funding target met is the (not terribly exciting) Oral Literature in Africa. At the moment three other books are gathering pledges.
You can "wish" that any book be unglued, and at the moment the most wished book is Hitchhiker's Guide to the Galaxy. That won't get anywhere unless the publisher is willing to agree an amount though.
The pledges start lower than Unbound, at $1 for an ebook, but to get your name it's more.
I think both sites are worth watching to see if the ideas work out.