Personally though I am hanging out for Windows 9 beta to drop.
I think the Car PC will be here to stay and I believe it will only become more mainstream as the technology evolves. With advances in x86 Android, or the convergence of the Windows kernel and OS the choices we will have let alone car manufacturers... What you guys do may be a bit of a hobby, but I think it will become big business.
Also the advances in hardware such as the intel's bay trail and AMD's Kaveri/Bemma/Mullins the options are so diverse, and not to mention SSD prices are at an all time low.
I am a complete noob when it comes to the world of car pc's, but at the moment Subaru make a pitiful double din sat-nav and a Car Pc makes perfect sense.