If I had a top body panel wish it would either be a floor board or rocker panel repair piece. Neither very good spots for plastic. Someone with a sheetmetal brake could whip out rocker panels pretty easy though. The floorboard is easy enough to use the old bend it over your knee method. I just have trouble finding the time to work on it. I guess that is the part I need the most,
time.
Another item that would probably be well recieved is a Windshield visor. I has to be well vented though, as most everyone I've heard of that has one has had trouble with vibration in the wind. My chrome metal one has a big raised area over the center that seems to eliminate that problem completely.
The dash is sort of like the holy grail to LUV truck parts. I've only ever seen one dash that was undamaged. The truck (a 1981) had been parked in a storage unit since 1981 until it was auctioned off in 1996 with less than 300 miles on the odometer. Not a single crack on it. I bet it is cracked now though, you could almost feel it cracking as the sun hit it for the first time in 15 years.