I have! and I have 2 of them Tubs that can house an adult boa, that is...(I do have 2 boas, but that's beside the point).

Walmart(the unfortunate place that it is) has Xmas tree boxes made by Sterilite. They are 52" x 23"?(I think) x 14" and have a latching top(that is incredibly strong). It's the same tub as the VE-175 tub from ReptileTubs.com.

I have a 7.5ft female in one and she is quite content in one of these for a bit longer. They are pretty easy to heat and clean and the lid doesn't need reinforcing to keep the snake inside

Oh yeah, and they run from $20-$25