Have you considered the Glock 36? it is also .45 ACP, but being a single stack, it holds fewer rounds, will not use the G21 mags, but is considerably thinner for concealment purposes.
I have the the G27, which is a .40 ACP, and it will use my G22 magazines.
One thing you may consider in a Glock is what are the other calibers you can shoot with it.
for example, I can get 9mm and .357 sig conversion barrels for the G22.
on a quick search I didn't find any conversions for the G30
Pops