This is a cool idea.
I'm not sure about the practicalities of it, but the concept is good.
There has to be some sort of sales tax / clipping the ticket to pay for the development of it.
As I see it, it would be a separate entity on the blockchain. Possibly developed by someone other than Steemit.inc.
I also agree than now would be a good time to get things rolling on this while the market is small. If you build it to scale well, then it is much easier to start with something small and grow it, than try to build something big from scratch.
Having done both, I know which way works best - at least from a developer sanity standpoint :-)