I think comma.ai, George Hotz self-driving company is doing something like that. He has previously posted about hiring contributors. They way they do it is that

I think comma.ai, George Hotz self-driving company is doing something like that. He has previously posted about hiring contributors. They way they do it is that they offer bounties [0] for fixing bugs or issues of different sizes. They also seem to have design challenges which offer paid rewards as well. [0] comma.ai/bounties