Innovation in aviation has never stopped. Designs that were first toyed with decades ago are continually revisited and explored. Aircraft that were experimental in the 20th century are still experimental if a perfected model has never entered production. The lobbyist can build models of many of these experimental airplanes and can even find drone replicas. It just boils down to knowing where to shop for these novelty items.
It is hard to find a model of a vertical passenger plane in the shopping aisles of a department store, but all sorts of replicas can be found on the internet. There are entire websites that cater to these very unique niche interests. It pays to visit and see what is available. If you are an avionics buff, then it is worth a shot. It might be impossible to find models of rare or experimental aircraft, but you might discover that someone has a kit or a blueprint.