Shoe.
I will second mike's link. The Digilinx product line up and development is well done. They are still working on the streaming video part, but there are other controllable solutions in terms of Video distribution. Your question did not go into detail as to what your customer is after. Digilinx will save you some time.
If this is going to be a one-off project, I personally would not be giving away my services under any circumstances. I may have an allowance for service and upgrades though. JMO.
I have not used the Crestron solution for controlling WM9 in windows, this may be another alternative. USing a CP2e with browser controll and a bullet-proof controller for your other source gear. Maybe some others out there can add to this part.