Acrylic will scratch, but it's much harder to gouge through than most of the thin linings I have seen. I'm not certain, though. There may be a really solid epoxy out there that the lizards won't rip through, or something that will work deep into the wood to make the wood waterproof.

I'm not too worried about warping with things like acrylic because I'd be bonding it to the wood. But the real issue is I'd not want the lizard's claws making contact with the wood and that causing the wood to decay from the humidity. Essentially I need something where over the next 10-20 years, I wouldn't need to do tremendous repairs. And since I need to do this for 2 monitor enclosures, keeping my prices moderately low would be a plus.

Now if some epoxy were to be solid enough to withstand scratching from lizard claws, that would be ideal.