Sounds like a couple recommendations for plywood over steel for the interior rear panels. Plywood would definitely be cheaper, easier to work with, easier to procure, and potentially sound better, but I'm still concerned about weather resistance and mounting. I'll be herculining (or similar) whatever we use, so the outside will be ok, but do you paint or herculine the backside as well? Also, how thick do you use? Seems like using thick enough for strength would end up causing fitment issues inside, ie; interference with seats folding down, etc. I would guess 3/8" or 1/2" would be needed, but that seems awful thick to be installing down the sides.
BTW, the top got pulled and it's maiden voyage made to Chinamen's a week ago. The truck and the boy did great, only needed a strap on the last v-wedge obstacle.
Any recommendations for neoprene or similar waterproof seat covers for the rear split seats? Someone recommended Cabela's, but they didn't have any that would fit the split rear bench. Nor did several other places I checked.