A couple thoughts -
How are you going to connect the touchscreen to the computer? If the epia will be more than 3' away from the lilli, you'll need to get some extension cables - vga and usb.
Depending on where the mobo is, you might want to put a usb hub up front.
I'm guessing you have the software covered because you don't list any.
A case? Maybe not, but you never know.
And you'll need some cables (4ga probably) to run from your car battery to the psu, as well as an in-line fuse for said wires.
Other than that, it generally looks good.