I've been looking at this cabinet for a basis for a Leo Gecko enclosure. I would put it on its side, remove the door to make an appropriate door for the tank, obviously....debating on a sliding door system or to make a door. I'd also cut a hole in the top to make room for grating / screen for ventilation. I am planning on using a deep heat projector for the heat and put in a uvb light.
The other option I would have is my book shelf itself. The dimensions of the area however would be 27" long, 12" wide and 13" tall...~15 gallons by online calculators. I would of course add a door system and go from there. Again, like above, I would do the same.
On either of these ideas, would you waterproof the wood with epoxy/liquid rubber?