We're looking to do online escrow for a site connecting freelance developers and entrepreneurs (matchist.com). Haven't been able to find anything that allows for credit card payments (escrow.com only does wire).
I believe Amazon's payment service lets you ice a payment (i.e. put a hold on the money) which can then be released/paid on a further signal (I think it's what Kickstarter uses).
However you should realize that any payment made with a credit card can be reversed, and there's no-way around that.
However you should realize that any payment made with a credit card can be reversed, and there's no-way around that.