The Glock 36 (single stack) and G30 (double stack) are probably the smallest.
I had one of the Questar G36's and it was 'snappy' to say the least!
I have also had the Ruger 345...not much larger than the G36, nicer to shoot and very reasonable..highly recommended.
The H&K Compact Tactical is comparable in size/ weight and also gets two thumbs up...( better quality, nicer controls, but twice the price of the 345...)
I have just picked up an STI RangerII...an updated Colt Combat Commander
with bull barrel, steel frame, Heinie sights and a very nice trigger...
I find that it's the most enjoyable to shoot because of the SA trigger and the
mass makes recoil less objectionable....
As a 'range' gun, it can't be beat for a 'compact' 45ACP, but in a CCW context,
I would probably go with the G36 or G30 for low mass and 'bet your ass' type of reliability.
Just like always, it comes down to personal preference in terms of cost,
trigger system, ammo capacity, etc.
