I used Polycrylic, a water-based polyurethane for the interior of my bearded dragon cage. I've been very impressed with it. I'm sure any acrylic latex paint would offer even more protection.
One caveat. My dragon scratched the heck out of the floor as did the shifting substrate, cage furnishings, etc. After a few months I decided to insulate the floor and covered that with a scrap piece of vinyl flooring. It has worked out very well.
So for species that love to dig and scratch but don't have high humidity requirements I don't think you need anything more than something like Polycrylic for a clear coat or a good quality acrylic latex for a solid color. Just make sure you put down something more durable for the floor.
I'm sure Toon already gave you good advice on what particular paints are good.
>>I also understand that latex paints take a long time to REALLY cure.
Nope, they dry very fast.
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Current snakes:
0.2 Gonyosoma oxycephala - (Silver/Yellow)
3.3 Gonyosoma oxycephala - (Green)
2.1 Gonyosoma janseni - (Black)
3.3 Gonyosoma janseni - (Black & Tan)