Will a .380 stop a maniac? It depends.
All evidence points to the fact that nothing will stop a determined opponent -- one who doesn't care about the consequences of your defense due to 1) experiece with gunshot wounds, or 2) impaired judgement due to drugs, etc. -- short of a well placed shot to the central nervous system.
My first real-world concern, if I have to use my weapon in self defense, is more about my ability to be calm and place my shots well. I expect that when the stuff hits the fan, I'm going to be rushed, nervous, and scared. I'm probably going to throw a couple of shots OFF target (or not directly on the optimum points.)
That being the case, I'm looking for the largest round I can shoot well under stress. For me, that's 9mm.
If you shoot your CZ-100 (in .40) effectively, and I were you, I'd work harder at developing a different form of carry, at getting a tuckable holster, or trying to do something so that "printing" isn't an issue.
If you can't find an alternative, then I'd consider the CZ-83. (But, keep in mind, the CZ-83 isn't ALL THAT MUCH smaller than the CZ-100) in terms of concealability.
And there's always the CZ-[7]5 compact.