Outsourcing EDW Applications

Im working on some research and was wondering if anyone can help me out. This company that I am researching for is looking for a variable staffing model to use when demand spikes. They are seeking this model with respect to outsourcing some of their Enterprise Data Warehouse Applications to vendors with whom they can form a relationship and call upon later down the road again when needed.

I am wondering if anyone knows companies that have been in such situations and what they do, their criteria for getting vendors and the training and evaluation techniques used, if anyone knows where I can find more information, and/or if anyone has a good solution.

Thank You.