Unfortunately, Lowes no longer carries the tan 31 gallon Centrex container. I am not sure of the long term durability of the one Dwayne found as a replacement, but it looks like we don't have many other options at this size.
I would recommend buying just 2 units and make one EarthTainer this year to check uV resistance. All construction steps should be mostly identical to the current EarthTainer Guide.
Raybo