OK, people are gonna laugh, but I've been carrying for a number of years now down here in the heat and have tried a zillion things, but the one I keep going back to when all else fails and I can't abide anything but a pair of shorts and a tee is crotch carry. Think about it...all but the perviest of society have been bred to not look at another's crotch, and a suitably sized gun (mine is a PPK) tucked into one of those cup holding jock straps--sans cup, of course--disappears but is quick on the draw if need be.
I have heard of people doing that and a local police officer was killed after placing a felon in the back of his police car when the felon pulled a .357 mag from the crotch. Sad part is the guy had been searched by each of four officers and all of them missed it.
For me, that would not work since I carry a full size 1911 and there is little spare room in the crotch area.