I just realised I should share my find.. I went to the hardware store (can't remember if it was menards or home depot.. doesn't matter) and I saw the bases for seedling starters (not sure the actual term here..) but they're the thing that catches the water drained from the seedlings. They are big, rectangular black plastic things. They seem a bit flimsy, but they've held up well with my Hogg island boa. They were less than a dollar each! I actually had to cut them down quite a bit for my 5 1/2' boa, so if you have a larger snake, check them out!
I found a pic of one here:
http://www.hydroponics-garden.com/rocstarkit.html