Terry Tussey has been working on a 1911 platform that is capable of shooting 6 different calibers just by changing out slide. Calibers are .22LR, .38 Spl, 9mm, .40S&W, .357 SIG, and .45 ACP
This is a great idea for restrictive places such as Europe. It also is a great idea for target shooters who want same trigger feel for different calibers. It does use different springs
Built on Caspian frame, one caliber is $4,999. Each additional caliber costs $500, with additional slides/barrels would run about $1200
American Handgunner article: http://americanhandgunner.com/six-calibers-in-one-tussey-multi-caliber/
From: American Handgunner