You just became my best friend!!!!!!In fact they do. I recently purchased a Olympic Arms .40 Caliber AR that takes factory Glock Magazines. (G22 15 round mags).
They also sell just the upper, and you can put it on any lower and install a seperate magwell block to use with modified uzi or grease gun mags. (I believe 11 rounders though).
Also, LDW makes an AR lower that fits glock mags as well.
I will say, that I have had to send my Oly back for some adjustments, so I have yet to shoot it and cannot vouch for the function of it yet. I hope to have it back in the next few weeks and I will be performing a complete AAR on it. I have also purchased some non-factory 31 round .40 Glock mags to test function with the rifle. They work great in my handguns, but have yet to try them out in the Oly. Those will be included in the AAR.
FWIW....
You have to keep me updated on this!!!