ZippyDan,
The only light smaller than the A2 which is also brighter would be the E2+, which is an E2 or E2e (not sure which) with a P61 lamp, modded so that everything fits. The P61 lamp is cut from its integral reflector, and I think that a washer is needed to space the lens up enough for the P61 lamp to fit, and so on.
this_is_nascar is the only one who ever did this and I doubt he would do them any more, given his recent exit from CPF.
IIRC, the light can't be run for more than a few minutes or it will go into thermal shutdown.
As for self defense, I'm sorry but despite what we flashaholics would like to think, a flashlight is NOT in and of itself a weapon of any kind and is only useful for self defense when combined with something else. So a strike bezel and some type of hand-to-hand training would constitute a real self-defense tool. Or a bright light together with pepper spray, like the TigerLight OC. Or a bright light and a handgun or billy club or knife. Etc., etc.
My landlord's dog is very undisciplined and has the bad habit of jumping on people, getting them muddy and clawing them. I hate it when he does that. He's a good dog and only wants attention, but it pisses me off when I get manure, and mud, and a rip or two on or in my jacket. I have tried discouraging him with 500 and even 800 lumens right in the eyes. It is remarkably ineffective.
A BRIGHT LIGHT ALL BY ITSELF IS WORTHLESS FOR SELF DEFENSE. Yes, it can give you a second or two of surprised advantage and temporary blindness. But so what? What happens next? The best action would be to run like hell in those couple seconds, assuming you have no real force option available.
Sorry to be an *** about it, but CPFers in general have this inflated notion of the offensive capabilities of a bright flashlight, aided and abbetted by the SureFire website and its literature.