A long, long time ago - about 40 years - I bought a 1/72 diorama kit. It was a German artillery gun (possibly anti-aircraft) with several figures, a destroyed building and a square base about 9" on each side. The gun came with wheel sets to be displayed mounted or dismounted. The kit came with a small packet of grass, plenty of bricks, sandbags and details to make it to one's tastes. There was a series of these kits, at least four I think, that could be put together to make larger dioramas.
This ringing a bell with anyone?