Just last evening I did a quick layout yielding 8 medium 8-frame supers from a single 4X8 sheet. At that yield one can afford to buy high quality ply and still come out with very economical hives.
I am considering trying hives from 2" high density insulation board. Similar yield, even allowing for some big finger joints to hold the polystyrene pieces together, and very economical. This stuff takes paint very nicely, so a good looking hive results, with the potential to last a very long time.