I'm sure I had seen somewhere mattresses, trash bags and the like. IIRC, the mattresses where not in 28mm scale, but in 1/35. Maybe with luck we can find 1/48 ones which suit better the GW scale. The thing is to look for that kind of stuff in military modeling, not in wargaming.
And since I was thinking something similar, I've decided to try with some hammocks instead, which can be scratchbuild at the propper scale (but yes, a dirt, filthy mattress with urine stain, vomit, blood and/or feces would be a lot better).
Edit: Not was I was looking for, but there may be:
Look for 1/48 furniture in shapeways (a bit expensive tho, this bed is 6€ and while may be ok to me buy an odd one, will be not to try to build a full hospital xD).
Edited by Brother Aiwass, 11 September 2017 - 08:39 AM.