Search:

These are really, really nice rifles but the price tag is... Ouch!

Hagn Rifles & Actions Cranbrook, British Columbia Canada

You might have seen this but this crowd make a similar rifle to what your trying to achieve but it's chambered in .22 TCM with pistol mags in either 5 or 17 shot.
...

I'd definitely be keen on something like this and look at chambering into a .22TCM like Wingman has done on his thread.

Two things I could think of from your design is

1. Scope mounts, drill...