Ok thanks. I have a 2003 Chevy Avalanche so I am not sure if this will work for me directly but it is worth mentioning if you are going through the trouble of trying to build something when you can buy an already working setup that doesn't require any additional hardware.
This board is less than $200 and may be the fastest ARM dev board out there with quad 1ghz cores and up to 4 video outputs. 1 Gig of ram onboard and can use LAN, Sata or MicroSD out of the box to boot from. I will likely get cheap SATA drives to boot from since I believe those are more likely to work without issue than MicroSD cards over the long haul and would be much faster.