Re: portable shooting bench--buy??--build???
It sounds like you are looking for a "portable" bench.
Double 3/4" ply top, iron plumbing flanges attached to the bottom for leg attachment, 1.5" dia threaded pipe for legs.
You can get as fancy as you want with top size & shape, adjustability of leg length, mounts on the bottom to hold legs for transport and so on.
On thing you may want to consider: A heavy bench is much nicer (steadier) to shoot from but if you have to carry it any distance from the truck you'll wish you hadn't built it quite so stout. [img]/ubbthreads/images/graemlins/grin.gif[/img]
I've got 2; a lightweight and a heavy, both portable.