Here's a picture of the beast.lol I built this float tank late 2009, and it served me well. I documented the whole build so I could help others build their own tank. If you're looking to build a custom tank this site will still help a lot!
If you're looking for the most affordable way to have your own float tank I would definitely recommend buying a Float Tent. These things are awesome! As a bonus they are also light and easy to ship so it doesn't matter where you are in the world.
Join the Floating Revolution!