KickstarterForum.org

Are there legitimate crowdfunding services that will work on a success basis? So, maybe a small fee up front plus a percentage if successful. Someone that will completely manage all the promotion so you don't have to do anything except answer their questions and maybe provide some raw content.

Short answer: In my experience, not good ones, unless you can be expected to be doing large numbers or they really love the product and are doing it more-so for fun.