As usual there's pros and cons to either approach. We love Kickstarter, and agree that the community is a strong asset...but we also believe a lot of project owners will benefit from an alternative approach that puts them in more control of their campaign (and provides continued follow-up with their users after the initial campaign runs its course, which is actually a hugely important aspect)
Chris - love your ideas here. I head up our API at Crowdtilt and spearheaded the CrowdHoster project. We're psyched to get cracking on features like this.
Product pre-sales drove Lockitron to create SelfStarter in the first place...clearly a huge use case. With our API we'll be able to get more creative with the payment flow, allowing dynamic cost calculation like you describe with different shipping scenarios.