I also second the recommendation to pick one of these ideas and focus on it first, as it will be a lot more work to get it working, documented, and tested!
I personally like the idea of getting a distributed SVD-based recommender into the project. The SVD works quite well and all we have now is a non-parallel implementation. However I support Jake's suggestion more that RBM would be most useful at the moment. Pick your area, dig in, and we can help you refine your ideas and begin. Sean
