sorry, I don't frequently read these boards so I just saw your post and figured I'd give some feedback 
For my tank I wanted to use full tank for water area and then suspend platform above it so it doesn't take from water area. I only have a 40 gallon so i wanted it to be 40 gallons of water.
So I put together wooden top (yey for home depot) and suspended cork bark from it. Just in case Hissy gets little too anxious and wants to eat my cat I also put up a "cage" to block him from leaving basking area. I just bought one of metal shelves in home depot and sawed it in 2. I put silicone on rough ages in case he ever reached it so that he doesn't get hurt.
It was very easy to build (if I can, anyone can
) and it's easy to slip on and off during cleaning.
Here's pic of how it looked a year ago, I got rid of plastic plant thing after a bit (actually I just dip little bit of it in so fish have somewhere to hide) and I fill it all the way to top
Rest of pics are in
http://www.bastaic.com/tank/
tank1*.jpg pics are turtle tank



