If you are using Minecraft versions 1.2.5 ~ 1.3 you can use this seed to gain a map starting in the center of a huge ocean biome on an island with 2 tree's a single cave and abundant in clay, the nearest continent is extremly far away with scattered islands around the area. A great hardmode map to start on with few resources and little space to hide from mobs at night.
[Image: http://i.imgur.com/OXulQ.png]
If you use this seed on versions 1.3.1 or 1.3.2, you'll be able to start on a rectangular island with missing chunks galore, and endless oceans. The same island above in the first pic still exists, but is located at 889x,63y,654z
[Image: http://i.imgur.com/GvyjK.png]
Enjoy the trippy adventures in this sea of oblivion!