As far as 1911-pattern pistols go, the 3.5 and 3.0-inch barreled models are probably the least reliable of the bunch. Problems include:
1. Less slide mass
2. Barrel unlocking angle
3. Feed angle
4. Less stroke for the slide fore and aft
5. Magazine spring tension
6. Recoil spring power
All of these factors must be balanced perfectly to assure reliable functioning. It's
reliability that is the most important attribute in a defense pistol. Gilt-edged accuracy is not necessary, and often detrimental to functioning.
If you must have a shorty (under 4-inch barrel) 1911, get one that has a ramped barrel, particularly on one that has an aluminum frame. This helps with the acute feed angle and helps to prevent the battering that would otherwise occur on an aluminum frame feed ramp.
Personally, I think a Commander-length barrel, not less than 4 inches, would be as short as I would trust completely. And it's the length of the grip frame, not the barrel, that aids in concealability. Here's my personal choice; it has the shorty frame and a 4-inch barrel. Completely reliable, and oh yes - plenty accurate.
John