I've been wanting a 10mm carbine but I don't want to pay $1400 for the Vector MP5/10 and I really want to get a Longslide G20 (G20L) in the future. So, I was thinking that I could buy a Glock 20 frame and a MechTech 10mm carbine upper for it and have a 10mm carbine for hopefully around $400. Then, I can purchase a G20L slide and barrel to add to the frame and I will have a great combination w/o paying for a regular G20 only to never use the slide and barrel again. What does a G20 or G21 frame go for? Brownell's had the MechTech Glock 20 10mm carbine conversion for $269, but is out of them, that would be a screaming deal on a 10mm carbine. Thanks for any help. It is really too bad that Kel-Tec doesn't make the Sub2000 carbine in 10mm for glock mags, they are ugly and cheap, but people report them to be very reliable.