I have encountered some interesting challenges online and I have come up with the following idea (may be it was thought before):
Forming a "brainstorming raid party", in which the "raid party leader (Or other colaborative way to organize it)" bring the challenges from those companies, submit on the Brainstorming.com webpage as a challenge and start collecting the ideas. The Ideas can be submitted individually on the company webpage, however, every one that gives an idea that will be submitted end up taking part on the raid, having a share on all the ideas submitted. If any idea is selected, or multiple ideas are selected, the whole team "raid party" gets an equal participation on the bounty or end up becoming one of the founders of the project.
The main concerns would be how to protect the raid party idea discussion as it may be open for collaboration (may be a set of 5 ideators selected by the raid leader and 5 ideators included randomly in a private idea discussion session).
The second trouble will be how to enforce the party cooperation on the exhisting company challenge systems (how to avoid ideators to steal each others ideas and how to garantee that every one gets the fare share by participating on the raid party).
This idea comes to me to solve the problem on how to make ideators get an income or a prize from ideas, considering what is already available (out of brainstorming.com), like company innovation challenges. How to connect fastly the brainstorming.com to the companies searching for inovative solutions
Maybe creating a pool of all exhisting challenges around the internet is a way to increase/create income for ideators.