Oh Good Lord! A clamshell .22LR double.

I think it's fantastic!

One question - should it be a .410 frame rather than 28ga.? Most of the
Continental double rifles chambered in medium bores (up to 9.3x74R) are
built on 28ga. frame size. An example: Curl's Francotte 9x57R SLE

Of course, the 28ga. size will result in a full-size DR rather than a tiny one
as often seen chambered in .22LR.

Curl