I love your ideas. I think this is so important in the workplace. I particularly love your sensitivity to privacy, flexibility to different preferences for rewards, supporting new recruits to participate, and the idea of exchanging skills and knowledge.
I imagine that you might need to prompt a few managers to start using the system to encourage others to do so, and that making it as user friendly as possible will help to make it manageable for people when they are very busy.
In terms of the skills exchanges it might be helpful to give people more suggestions to prompt ideas, and perhaps to link this to skills gaps in the organisation.
Very best of luck with it and I really look forward to hearing how it works out!