Not sure if you're even considering this for a first release, but on the matter of the "backend" server that would handle all of the things that the ipad couldn't do (ie: interface with unsupported peripherals like sirius, fm, etc). What I think would be a good solution is to create a framework where others could add "plugins" to it. So say you have a base framework, and others could write plugins for support of other devices, which then would obviously communicate with the ipad over ip in a standard provided by the actual frontend. Just spitballing ideas. I'd really love to transition to an ipad in the car, but only if I can get the same functionality as my current carpc, or at least close to it.