Establishing a bounty construct seems like an interesting, and complicated, proposition.
Shall a seeker be required to pay the bounty amount upfront, to be held in escrow by the Q2A-powered site? Is the site operator expected to intervene and mediate any disputes between seeker and respondant(s)?
Across various 'lancer sites, I have repeatedly experienced the scenario where a "seeker" fields a question/request, receives multiple worthwhile responses... then neglects to acknowledge/accept ANY of them! Worse, seekers too often take a shotgun approach -- posting same RFP to multiple 'lancer sites, certainly without the intent to pay multiple respondants.
I believe the kickstarter(dot com) approach, enabling MULTIPLE seekers to pledge a bounty amount toward a given project/solution, has merit. As a platform, perhaps Q2A could be modified to "fit" that usage model... but building a kickstart-like app from scratch, with attention to its defined goals, sounds like a wiser choice, IMO.