When I first thought about this, I also landed on the public bounty method. The problem with that is it lets monied interests own everything. If you, a small creator, make something cool, there is no bounty you can set that Disney can't afford, and once they make it public, they can certainly exploit it better than you can.

As for revenue accounting, it's actually pretty easy (for some definition of easy). If someone else used your IP and you had to sue them, how much would you sue for? Use the same method to calculate your own income. Yeah, it's definitely a jobs program for accountants and lawyers, but overall it provides a strong public benefit.