Have fun trying to get media center IPC to work reliably. I have an old contract that prevents me from helping out with these types of projects but I will say you picked a very difficult platform. WMC is designed from the ground up as a media center, once you start digging into the sdk you'll realize how brutal that can be for a carPC FE.
Microsoft of course has no incentive to extend MC for automative use, as they already have a product (Windows Automotive, which powers the Ford Sync and the likes) for that. However, Windows Automotive is for the most part not a DIY option, as most people can't even get it, and it's an embeddable type system.
I do believe that MC can be "made" to work the way we want, for automotive use, even though the integration may be less than ideal. However, I don't think that's any different from a lot of the integration being done with most of the popular front ends. As Mitch said, it just requires more work than normal.
I going to try to run Media Center 7 for a week in the car and see what happens. As I said, I don't use phone or nav since I have the OEM units. My MAIN concern is library management, specially playlist selection and media playing. Reliably. My OBDII stopped working, I think I'm just going to miss G.Earth and Traffic. My Minicam Starts with windows, so no problem there. What else I'm missing? Twitter, all those toys...
Let's see what happens.
I wish my carputer was that reliable - and usable. My wife knows everything about the WMC, but the carputer, she is only interested in Media playing.
That's the power of a good front end, I literally gave her a 5 minute primer, showed her how to use the SpaceNavigator, and that was that.
The question I would ask is: Will Microsoft use MC as the foundation of it's automotive media management? It seems like a logical move, and they certainly have the development resources to make it happen. Of course, you would only be able to get it in a Ford