Fantastic idea. One possible way to implement it would be this:
A randomised draw amongst the entrants. Would have to have some sort of control to ensure not duplicate or fake accounts.
The winner posts 10 new steemit posts, and everyone who wants to contribute to the winner can go down and upvote all 10 (or a few). Or just send them Steem.
Another idea would be to delegate steem power to one user for the period, then after the next draw all tje delegated power could swap to the new person.
RE: We should start our own Steem #MillionaireMakers drawing just like reddit.com/r/millionairemakers! Would be much easier to do within Steem anyways.. and much more effective!