I've mentioned Innocentive a few times on this blog. It's a business that acts as a matchmaker for organizations that have problems, typically of a science or engineering nature, to solve, and people who solve the problems. Each problem comes with a cash prize that's awarded to the problem solver.
The TekScout Open Innovation Network seems to operate on similar principles. It has problem categories like "Life Science, Chemistry, Math and Computer Science, Physical Science, Engineering and Design, and Alternative Energy/Sustainable Products". That's an organization fairly similar to the Innocentive one. It does seem like the prize amounts tend to be relatively high on this one, with prizes over $100,000 being common. They allow a model that sounds a bit like COTS where payments can be made as milestones are reached. It looks like there's flexibility to make arrangements similar to the prize competitions of this blog or closer to more traditional models.