I have never seen them in any form for modelling. As a mater of fact, the only time I have seen them is when we land at casualty receiving and run inside to steal supplies.
The only medical facilities I know of are the Verlinden "MASH" tent in 1/48 and Italeri has an "Aid Station" in 1/35. The verlinden set is only a bare bones shell of a korean era GP (small) tent with poorly molded flaps and windows with a red cross decal for the roof. The Italeri kit is a field expedient aid station with some 2x4 posts and a corrugated tin roof, but it does come with a litter and some WW2 equipment.
I would think (key word is "think") you could make a Trelleborg section fairly easy using styrene strips for the frame, sheet styrene for the doors and tissue for the outer shell. What scale? That's gonna be huge in 1/35 even if it is only one section. If you go for it make sure to post some pics!
What unit are you with?