If you are set on a 1911 platform, a Glock isn't going to do it for you. That said, if you would consider a Glock, Lone Wolf makes a 6" top end for the G20. My G20/21L below is a custom Glock I made in 2005 with Lone Wolf's help and it's popularity influenced JR to develop and release his line of stainless steel slides.
It started life as a G21 45acp. I found and added a 6" German steel slide and Jarvis 45acp barrel to it in late 2004. A trigger job and some extended controls made for a sweet shooting, accurate 45acp. The 4¾ oz heavier slide/barrel really helped keep the sights on target and soaked up a considerable amount of recoil energy making for a soft shooting 45.
Soon after, I got a wild hair to develop a conversion so it could shoot 10mm too. After talking with Kevin at KKM about my idea, we agreed that it was possible and so I asked him to make me a conversion barrel for it. He agreed and it now carries his first ever 45-10MM conversion barrel. With the barrel and G20 mags I had the first ever 6" G20/21L as I named it.
After shooting it for a few years, I decided it needed an update so I converted it to a USPSA 'Limited' configuration which included having the slide hardchromed, rounding the trigger guard, adding an extended mag release, replacing the Bo-Mar front sight with a Dawson FO front sight, and adding a Lightning Strike magwell. I also installed Scherer +2 mag extensions giving me 17+1 rds of 10mm capacity.
17+1 rds of my hot 10mm loads make this one fire breathing shooter but because of the polymer frame flex, it's surprisingly easy to shoot. Even 200rds of hot 10mm won't tire out my hands or wrists at all. Try that with a 1911 framed 10mm. It's also surprisingly accurate even at long ranges. 100yd shooting is POA and I regularly shoot it at our steel targets at 200yds offhand. While I don't hit it every time, I feel that's pretty good for open sights and 63yr old eyes.
Best of all, with the magwell removed for hunting, my rig as seen above actually weighs less than a 5" steel 1911 with only 8+1 rds aboard. As expected, the 6" slide yields a 28% longer sight radius which helps significantly and the 6" barrel really allows the 10mm cartridge to perform up to it's full potential using the slower pistol powders such as my favorite, AA's Power Pistol.
To establish the performance available with the 10mm rd, I've chrono'd my 'nuclear' hand loads from this pistol. The data below was generated using an Oehler 35 chrono on a 84° sunny day at our range which sits at 6,100ft asl. I fired 2ea, 10rd strings and averaged the results.
180grn Speer Gold Dot = 1,423fps and 809lb/ft ME, Std Dev. 13.14
165grn Speer Gold Dot = 1,503fps and 827lb/ft ME, Std Dev. 9.93
