A rather unique take on the 1911 is the Italian company Arsenal Firearm's product, the AF2011-A1 double barrel pistol. The pistol evolved from a Swiss machinist's foray into a double barrel Sig 210. With the thought that two bullets knocking down someone is much better than one, and without all that double tap nonsense, This new 1911 might be what you're looking for.
It seems like too much gun to me. The 1911 is already heavy, and two of them welded together along with 16 rounds of 230 grain .45's would be quite a handful, althought the weight would soak up some of the recoil of two bullets being launched simultaneously. One would also doubt if it was necessary, seeing as how one .45 bullet at a time is already a proven manstopper. They do mention in their literature that they can take down a bull, if you really need to do that with a handgun. Will be a great conversation piece.