I carry a Kimber Pro Carry Stainless (4" Stainless with alum frame) in a VMII. All day every day.
I wouldn't have any problems carrying a full size 1911, the length of the slide doesn't any real difference if you are carrying IWB, the handle is the only part that is visible and distinguishable, and if you have a good holster and a thick gun belt the weigh isn't that bad at all.