Here is my idea...maybe you or anyone else can comment or add something to it:
Laptop w/USBs and video-out, mounted either in the trunk or under a seat.
A head-unit with audio inputs AND video capable (folding screen)
USB hub(*) mounted somewhere in the front (need for keyboard, pointer device at minimum, possible jump drive or zip disk for MP3s, etc).
Interface for ALDL or OBD II to monitor engine functions.
Hardwire a remote power button for the laptop so you can power it on w/o actually going to it.
I'd recommend either an IBM Thinkpad or a Toshiba Satellite as those seem to be born, not built (die-casting...a lost art indeed) and will hold up well in an automotive environment.
Nothing Ebay can't help with.
Welcome, downwardly mobile yuppies, to the dawn of the Age of Nefarious.
1993 SSEi - FrankenJinx - dead and gone.
1994 SSE (136K strong) - 180* t-stat,HD alternator, most unequipped SSE on the club, XM radio, Kenwood CD/MP3.
2006 Chevy Malibu Maxx LTZ - Custom 2.25" manifold-back exhaust w/FM-80. Probably the only Maxx with this system.