I know the idea of running games with a USB loader over a network has been discussed before and it's 2018 and all, people are done with Wii. But I had an idea. This is just theoretical but I think that using something like a Raspberry Pi Zero or similar device might be able to accomplish this. The Zero can run in USB OTG mode and appear as a mass storage device:
https://gist.github.com/gbaman/50b6cca61dd1c3f88f41
The tricky part would be linking the network share to the USB OTG but I think UnionFS might be able to do that. Perhaps a combination of a network share, UnionFS, and USB OTG... I dunno. Could it work? I don't have a Zero or an A to try. I have a few Bs but B can't use OTG mode. Maybe the 3B can, I dunno. There are likely other devices that can do this but the Zero is $5.
https://gist.github.com/gbaman/50b6cca61dd1c3f88f41
The tricky part would be linking the network share to the USB OTG but I think UnionFS might be able to do that. Perhaps a combination of a network share, UnionFS, and USB OTG... I dunno. Could it work? I don't have a Zero or an A to try. I have a few Bs but B can't use OTG mode. Maybe the 3B can, I dunno. There are likely other devices that can do this but the Zero is $5.