[Pumilo]

Hopefully Doug (pumilio) can estimate your glass needs. For bg and false bottom your looking at a minimum bill of $50 at the hardware store. The bigger the more money lol.

Sorry, I work with dual pane insulated and get all my single pane as scrap so I really can't say what a retail outlet would charge. All my vivs were free, as scrap glass.

 

[Pumilo]

1/4" Would work good and 3/8" would be great! You could go thinner if you built a steel frame, the frame would take all the stress off the joints.

Building a tank is not to hard, it's even better if you have help. You will need a very very sturdy table, with a nice flat top!
Here is a used tank that is fairly close to you. It's really big, but you could modify it! AUCT Arboreal Lizard Vivarium - Vivarium Forums

Here is the tank I made.

I would agree with that. 1/4 inch if you are careful. Here is a nice build link. http://www.dendroboard.com/forum/parts-construction/63870-building-glass-vivarium.html