This should probably be moved to the proposed setup forum (its at the top of the page in the newbie section)
I'll give you a some suggestions anyway,
Comp Internals: I would skip the SSD for right now, just get 1 regular HDD. It will function just fine without any problems,everyone uses them, and SSD Dollars/GB prices will come down drastically in the next year or so anyway.
For bluetooth, just get any old adapter, get one thats 1.3 (I think thats the newest) they're all about equal.
Touchscreen: Look into fabrication, search for you Year,Make,Model see what others have done with your car.
Front End: I highly recommend Windows XP and RideRunner
Controls: You don't need a mouse/keyboard. I have a wireless keyboard with a thumbstick for mouse control, I only need it for maintenance
Head Unit: I don't run one, some people do. Its up to you, you don't need one. Its completely possible to build a nice system without one. But again you need to do more research to weigh the pros and cons