The Bobcat thread got me thinking again about some G10 grips for my 21A. I briefly looked into it a year or so back with no luck. I used Larry Davidson for similar projects in the past, but sadly he has retired.

Any leads on someone that could/would make some custom G10 grips? I'd like something similar to the Simonich "gunner grip".

I don't know for certain but you might try Cherokee Hills.
Bob makes outstanding grips.
http://cherokeehills.biz/