Greg,
Search for the post, "Find Source for Fuel tank" you will find a lot of info, including my post. I had two tanks made from 3/16, both 75 gallons and they were angled to match the hull. They cost me arbout 1700.00 to my door (200.00) shipping for both. If you have a DHL account, and you have them shipped DHL you should be able to save a lot over UPS.
www.speedytanks.com, ask for John. Your rectangular 58.0 gallon tanks shoud be cheaper.
PS, Pics are coming soon, I had to go back to work !!!
Good Luck,
Dan