Hmm... I think it's a personal thing. I've carried a G19 in a Kramer IWB, but I didn't particularly like it. I much preferred a 1911. At least the very smallest Glocks have a bevel on the front end. I suppose that helps a bit.
I know Glock has made some single stack guns. In fact, if I wasn't a dedicated 1911 fan, I'd consider a G36 (I am a .45 ACP fan). But, so far, I don't think Glock has tried to make a really slim and comfortable concealed carry piece. Maybe they should check the sales figures from Kimber's Solo and a few of Ruger's smaller pistols. I think Glock could make a great IWB concealment piece if they so chose. Imagine if they decided to one-up the beautiful Browning Hi-Power with its slender slide and only moderately wide grip.
For me, the Glock is just too "blocky." I'd relegate it to OWB carry or fanny pack if that's your thing. I've briefly worn a Glock in a horizontal shoulder rig, but that's not my favorite way to carry, and I didn't much enjoy it. Still, we're all different. Maybe my body has "worn in" after all those years with the 1911, so it fits me. I'm all for trying out a gun and method of carry, if possible, before spending the big bucks on it.
Maybe someday... If Kimber can apply themselves to making a nice concealment piece like the Solo (which reminds me of the 1903 Colt), then so can Glock.
Until then, good luck.