Like the idea. What is the cost of neoprene though? I checked one site and a 51" x 83" piece is 89.80 USD.
The foam board idea sounds awesome. Checking home depot.com I found a 1inx2x8 piece for 10.58 USD. Color would be the thing though which could possibly be solved with some black primer/spray paint.
OP- I have used 1 Zilla UTH with great success; Zoo Med, not so much. Good thread btw.
Rosey- ty for the link for the Ultratherms, I'll have to check one out. :-)