*breathes in*
BWOI.
https://www.octagonairsoft.com/product-page/king-arms-tws-6-inches-m-lok-9mm-carbine-gbbr-bk
So Octagon Airsoft is collecting preorders for this thing - a King Arms GBBR running off Tokyo Marui/WE Glock mags. Available in black and Dark Earth, with a 10" or 6" barrel.
Since I already have a 50-round TM Glock mag for my BRRRRT, I am thinking about doing things involving this, a HERA stock and an ACM Vector-style mag holder.