As is probably known, I consider the current Heep entertainment package to be somewhat limited and proprietary so have been rolling my own.
Started with Android but have moved development to Windows based systems since completly open, are many legacy products (including camer input and engine diagnostics), and can layer on much better security including FDE.
My current system is centered on an Acer W3 8.1" tab with Torquescan, Delorme Street Atlas 2013+, Microsoft Office, and EZCap for the rear camera (personal preference, YMMV) and a second 7" monitor for display-only elements.
Along the way I have found that all 14 episodes of Firefly, Serenity (in HD), and a coupla hundred music albums fit on a single 64GB microSD.
Am also using a Verizon MiFi unit to create a hotspot and router for a wireless based LAN storage unit (have 120GB SSD, larger are available).
Nice thing it that I can pop out of the car and either use as a real desktop with KVM or show movies on a big screen.
Not for sale, this is my playtoy and Bay Trail is supposed to be out 4Q13 but just wanted to let you know what is possible today which is a lot more than just a year ago. Everything except the MiFi is available from Amazon (plug) and quite inexpensive, am just using the GC for amp, speakers, and Uconnect.
ps I know how bad the power system in a car can be so my systems have conditioned and controlled power. There are a number of inexpensive (under $10) LM2596 based systems that are very good at cleaning up 12vdc and make a cheap fuse if a surge occurs. Just a thought.