Mike, what I did to catch scumbags like this was to buy a dash cam. It records on a mini sd card that you can use on your computer and get footage of the truck/car, license plate etc. and time it happened. Mine has a wide angle lens so it picks up just about everything. I bought mine on Ebay but Fry's has a large selection too.
Check'em out. Sorry 'bout you truck and hope someone reads your post who might be a witness.
"Sometimes there just aren't enough rocks"