Ebay deal for a 12.1" CTX Panoview. Looking at the description (might be worth checking with the vendor), it has serial touch included. And has a buy now at £200.
I've used a Taxan CV600, which is a CTV PV 550 rebadged, and it is plenty bright enough except in direct sunlight, without having to mess with the brightness/contrast.
4x4 in a turbo stylee.