ady, this has probably crossed your mind, but would your sets be re-usable for your various PT edits in some capacity after some tweaking/repainting? i understand you can't store them, so i guess you would have to make whatever footage you need with them when theyre built.

my friend who is a stop-motion animator often plans projects a few months in advance so he can pre-recycle sets when theyre built. (he also has a space management problem) he is currently doing three different films with the same model hospital ward! (i don't know why im telling you this.:P)