cw308's comment started me down the rabbit hole of dimensions. As I commented earlier in this thread, both the Springfield 911 9mm and the Sig P938 are expanded variants of the Colt Mustang clones, and the Colt Mustang itself is a clone of an earlier Spanish pistol. The 911 and the P938 are sort of "1911-ish" in their placement of the operating controls, but the resemblance ends there. That got me wondering how much of a size advantage do those guns actually provide over small models of "real" 1911s. So I looked.
The 911 and the P938 both have 3" barrels and are 5.9" in length. The 911 is listed by SA at 5.9" high, the P938 is listed by Sig as 4.3" tall. I can't explain that difference, as the guns appear to be pretty much the same. Maybe on includes sights in the height, the other is measure to the top of the slide? Dunno.
So then I went into the archives of the M1911.org on-line magazine and dredged up their review of the original SA EMP. The article provides a dimension comparison of the EMP against a Colt Defender and a Para-Ordnance Slim Hawg (which is even smaller than the Defender). Here's the chart (reproduced by permission):
They are all 3" barrels. The "real" 1911s are a tad higher, which probably isn't a significant factor in concealment. The "real" 1911s are somewhat longer, and that's probably mostly in the beavertail grip safety. The thickness seems to be the same for all of them. If you were comfortable bobbing the beavertail, the length could be reduced by shortening the grip safety.
For someone who wants a 1911-like pistol, I don't see much reason to buy a 911 or a P938 when there are any number of "real" 1911s that are not much larger.