You know it's only a matter of time before something like this shows up. Pledge bitcoin to fund underground projects such as: illegal art installations / street art, drug labs, 3D-Printing Weaponry development and research, civilian post-apocalyptic fallout shelters, cloning technology, sex robots, starting a chain of brothels or even starting a new country! The possibilities are endless and scary.
As absurd as all that may sound, it may not be 5-15 years from now.
This will be extremely difficult to prevent scams. The only reason why Kickstarter works it's because they can somewhat verify the identities of the people involved. With a Darknet kickstarter, the whole reason for it to be darknet would be for it to be anonymous. In other words: there is nothing that would prevent someone to start a scam there.
On the other hand, if you would implement some sort of escrow within the service, it might just work.