yeah some one get on that, i'd buy one.
There are a few others...expresscard is, after all, just a link to the PCIe bus. No problem at all doing high-res VGA out (and the HP ones have digital and analog audio out along with it). In fact, there's a module you can get ($$$) that will house an outboard PCI express video card. The new ViDock (coming soon from the folks that make VTBook) is also basically a video card that fits in the expresscard slot.
To the OP: Turbocad is one of the more experienced members of the board, I'd take what he says to heart. I'd do a trunk mount with a regular dock, if one is available. You don't want to be sliding things in and out of drawers and under seats, not for a system that depends on multiple wire connections. That's just asking for inconvenience and eventual failure. A dock is meant to be connected and disconnected routinely, and gives you access to a power switch you can mod without molesting your lappy. Don't underestimate that if you are looking to build this into a sleek and easy to use system. That, and your odds of being the victim of a smash-and-grab go down considerably with the laptop in the trunk.
I have too much time and too little aggravation in my life, so I built a carPC. ;)
ok thanks guys. good tips but my problem now is i dont have a trunk, its a s10 blazer. but i was thinking i could hang it from the headliner and then reapolster the headliner so it looks good.