It does not seem as if it would be too hard to make a bullpup stock for the Mini.
and the basic format could extend to 10-22, M1 carbine, M1 Garand, M1A, SKS, and AK rifle types.
Just getting the right angles, trigger link, cheek mount, sight mounts and types, and the 1001 other things that will show up when this is attempted.
There is a bullpup stock for the Garand seen on the internet.
And there is a reason they want the coin that is quoted on the website.
Tell us when your design is ready to test.
Please, I like the concept, now go find a design and manufacturing team.