This popped up on Facebook. They offer structure kits in all scales. The G scale ones are affordable by current standards, though I’ve no room for any of them.
This might be a good option for those without a 3d printer, but it looks like he’s finding freely licensed STLs and scaling/printing them himself. For example, his power station is a free STL on printables. While technically legal (depending on licensing of the original) this is a grey area. And just scaling STLs often leads to questionable quality. Buyer beware.
