Good info. Thx alot for sharing it.
I think I am going to go with the pond PVC liners method. Since this tank wont be holding water (it's for my Tokay Gecko) I am going the more inexpensive and easier route. I will only be misting once a day and keeping the humidity as high as 60% thats it. So I think the PVC liner might work best.
I have some plastic sheat material that might even work better than the PVC liner. Its made to keep moisture from leaving your bathroom into the walls. And since me and my fiance just redid our bathroom, we have a ton of it left over. Also, silicone seemed to stick to it pretty well, so sealing the seems should work out really well. I will try this method and post a constrution journal of the whole process as soon as I get the wood and start to build.
Thx alot for all the help guys. I needed a good group brainstorm.