Have you looked at the Glock SF (short frame) models. In the .45 they are available in the 21 and 30. Short frame gives you a smaller diameter grip by deleting the backstrap cavity. This might be what you're looking for.
Go shoot the XDM9 in the 3.8inch sub compact configuration. You can carry either 13 or 19 round mags. 13 is great size for cc. 19 is great for range days or when hunting someone down.
Looks like my issued M590 except the shorter mag tube. You can't go wrong with this thing. Put 8,000 rounds through one at a school. No failures. My shoulder is acheing just thinking about it. Someone get this.