G39 slide on a G38 frame-Can ya?
Crazier things have been asked, but will a 39 upper fit on 38 lower? I realize a bit of frame will hang off past the barrel, but I think that could be trimmed back if the upper would function properly.
I don't like the AG extensions as they just look unfinished. The above concept would give you somethin' akin to the older S&W "SSV" guns.