Interesting question.
A neighbor of mine just got a 'Randall' .45 and I got to shoot it last week. It felt, at least in my hand, perfect.
So I did some homework and discovered that the Randall had some meaningful positive change to the overall 1911, mostly materials and "mirroring" the 1911 for left handed shooters.
http://www.m1911.org/mod_randall.htm
So your post got me thinking...one of those question yo think you know the answer to but want to buttress your knowledge a bit. More interweb detective work and the consensus matches that of the replies here. I did find this site that is really cool. Spend some time on it and you can see ALL the working of the 1911 customized.
http://www.m1911.org/loader.swf
I've only own two 1911's and a Browning Hi-power.