You've got almost the same setup as me. I've got the MII12k, the VoomPC etc. But I've got a 6,5 inch BMW screen, 400x240.
There is one problem though!!!!
The only widescreen format supported by MII12000 (disregarding what you can set in Bios) is 848x480.
Information about your screen is - Resolution 720x400 to 1280x1024 - (!?!?)
My tip is that you make sure that your carputer supports the native resolution of the monitor. I ended up with an awkward solution with extra graphics board and modified VoomPC box. You can have a lock at my site if you like, even if I'm not quite done.
Keep me posted.