Thanks to the always wonderful Matrix Synth for alerting me to Robert Schroder, some kind of German new-age synth pioneer guy. On his website, he sells a kit to make a 1/10th scale model of his studio (Atari ST, Roland XP-60 workstation from 1998, old Tascam desk, antique Sony F1 betamax audio recorder). Each item is sold separately, as a flat piece of card. You have to cut it out, fold it, and glue it yourself. If you bought the full studio, it would cost €281.50. He'll cut them out for you, if you're willing to pay around €500.
By comparison: here is a completely free papercraft Moog Modular, here is a pre-cut, pre-scored Arp 2600 for €15. Then, of course, is the mind-bogglingly beautiful and awesome work of Daniel McPharlin, who builds beautiful little cardboard synths and sells them (very quickly) for €60-80. (via Matrix Synth)