this one should get you some nice overhangs in 1.3.1 for sure and I doubt the map generation changed much into 1.3.2. Keep in mind though that because of the large biomes things are spread out a bit.
and some pics:
a little history for no reason in particular:
I started using the '-john crichton' seed as early as beta 1.3_01 because I discovered it tended to generate maps with crap tons of caves. Later on it always spawned me in jungle biomes which i hate so I stopped using it. I tried it again with large biomes on recently and liked it a lot so i posted it because I found it difficult to find good overhang/floating islands map seeds for 1.3.1/1.3.2. anyway if anyone tries it out, I hope you enjoy it.