i take it this is for a older 80's-90's silverado?(i believe they did a major dash update after 2000--that allowed for 2din radio's).. my dad had a 91...
i do not feel comfortable recommending any computer-compatible motorized displays-- since the last reviews, lilliput updated their model to use metal gears-- the previous models had plastic gears that stripped from use(so it is quite possible the new model will last, but @ ), but other companies have had motorized models and all have had problems within a couple years of use. motorized screens really haven't been used or recommended around here for the last 3-4 years now because of all the large quality downfalls.
on the plus side, all the vga compatible screens i can think of also have at least 1 composite input-- the type of input that a standard car dvd player uses, so it should be perfectly possible to have both a carpc and a separate dvd player(though, why not use a dvd drive in the carpc, and just play the movies through the carpc?).
otherwise, just be sure to look around (check out 4ofakind's mid 90's build in the worklogs section!). i can almost guarantee that nearly every idea you can come up with, and then some has been discussed and built in one form or another, and if not, i want to see what you can come up with!!