Cork: You might want to also consider a couple of different angles to your problem.
One angle already mentioned is that of the shoulder holster. Being in FL, you could get by with very loose fitting shirts--and you could wear the shoulder rig under your summer weight shirt. I recently bought a shoulder holster due to some lingering hip issues. Andrews custom leather makes a really nice quality shoulder rig.
http://www.andrewsleather.com/traditional.htm
One other angle is that you could get a smaller pistol. I carry 1911s, so I understand the angst at the thought of going to something smaller, but that still might make the problem a bit easier to solve. There are lots of high quality, smaller pistols out there.