As a fellow 5'6" person, I can recommend the 1911 platform rather highly. I carry a Kimber Ultra Eclipse IWB; it completely disappears on me, is lightweight enough that I can carry it all day (although I've never minded the weight of my 5" 1911 either), yet is heavy enough to moderate the recoil to a manageable level. Yeah, it's a chunky-looking pistol, but that's mere appearance; with the proper holster, no one will be able to tell it's there.
Even with a 4" or 5" version, the hardest part to conceal is the grip. Careful "blousing" of your shirt around your waist will moderate that; while you'll likely never be able to "completely hide" the bulge of the grip, you CAN make that bulge blend in with the folds and falls of the fabric. Conceal that, and you've got it made. The rest of the gun is rather slim; I only have to let my belt out a notch or two at most to accomodate the pistol.
And that massive hole in the end of the barrel is pretty intimidating from the "wrong" end, too...
