My advice is don't do it unless you like to build things and you have the tools, namely a table saw to cut sheet wood. I am finishing up a 3x2x2 based off of this design
http://www.mccarthyboas.com/EZ_Prints.html. I am using 3/4 " birch plywood and instead of using Edge banding I am trimming all exposed plywood corners with 1 1/2" corner molding.
4x8x3/4 birch plywood 45$
trim 40$
glass 30$
glass track 16$
nails/screws 10$
liq nail/ silicone 10$
Urethane 15$
sandpaper 7$
Vents 15$
total rough estimate 188$
This is just a rough material price list without taking into consideration tools, saw blades, clamps and so on. Honestly this project is more trouble then it is worth for someone like me, the non furniture building type, lol. I just bought a BoaMaster 3ft b dragon enclosure with screen top for 180 shipped,
http://boamaster.com/catalog/Cages-3-1.html , check out their prices. These are the same setups Carolina Classic Dragons uses
http://www.carolinaclassicdragons.com/den.html.
Even though the cage I built is 3x2x2 , it is heavy as hell. The time and effort to cut, assemble, sand, stain, and seal is alot. If I were to do it over again I would just get these
http://dragons4you.net/Cages.html , they are so light I heard you could play catch with them, lol.
If your handy go for it but i just wanted to share with you what mowing the grass was like on this side of the fence. If you still want to go ahead check out " How to Build a "NICE" 2' x 4' Bearded Dragon Enclosure " by
http://www.rioreptiles.com/instructions.html. This design will be a little lighter and should go quicker if you have a nail gun but the wood they uses is like what hollow cor doors are made of and you can buy 3/4 birch or oak for around the same money. Man, don't Rioreptiles have some sweet dragons for a great price.
Melamine is heavy and the prefinish makes it easy to clean along with enabling it to wear well but it is a pain in the butt to cut without chipping. You can buy a special blade which is insanely expensive and doesn't last long or you can half rip/double cut the boards on a table saw. I found a local cabinet builder who would rip melamine for me but the total cost of cuts was 45$ on top of the board cost.
Good luck and take pics of what ever you decide to use/make.