Sorry I missed this thread for so long, hopefully I can help by adding my thoughts.
I've never understood or agreed with the notion that glass terrariums are only appropriate enclosures in certain parts of the world. In my opinion they can be used very effectively in more places than they can't. Few of us live anywhere that we can keep all of our chameleons, particularly montane species, outdoors year round, thereby forcing us to maintain them indoors under artificial climate control of one type of another. If you live up north, the cold winters make maintaining humidity complicated making glass terraiums great to fix that. In the south, the air conditioning we use to keep the house cool dries the air, also making glass terrariums ideal. If you're keeping your chameleons indoors, there is a good chance glass terrariums can be used very effectively if done correctly.
I typically do not recommend glass terrariums for larger species except for raising younger animals and possibly females. That said, Exo-Terra is now producing a 36"x18"x36" terrarium which in my opinion could house an adult male veiled or panther provided it was not an individual who roams a lot. Ultimately it will depend on the individual but this sized enclosure would be completely suitable for many individuals. That said, I would not recommend the 36"x18"x24" for an adult veiled or panther.
For the 36"x18"x24" terrarium, I would recommend a single individual of the smaller true chameleon species (jacksonii, multituberculatum, sternfeldi, etc.). While some of the smaller of these species might do well as a pair in a cage this size, attempting to do so is definitely an advanced care technique that I would not recommend to the OP having never kept chameleons before, particularly these species. One thing to consider, however, is that many of these species are primarily available as WC and acclimating a WC chameleon in glass terrariums is more difficult because you are limited in the amount of watering you are able to provide. Thus, I would recommend making sure to get a well started CB specimen and as a first chameleon, I would recommend either a CB jacksonii or sternfeldi if you were going to go with a smaller montane.
Similarly, I would not recommend cohabitating other herps with your chameleons in this enclosure, particularly as a new keeper. There are too many factors which you simply can't read about to be prepared for that go into this type of attempt. I am about to start setting up a 36"x18"x24" Exo Terra glass terrarium with a group of pygmy chameleons and williams blue day geckos, but these are very small species for an enclosure of this size, they are of approximately the same size, they naturally live in the same habitat, and I have a lot of experience to watch for problems. It isn't something I would recommend a newer keeper ever attempting, however.
As has been mentioned, lose the waterfall. They are breeding grounds for bacteria so unless you are going to completely disinfect it every other day, I don't think they are worth it.
Just to reiterate, these few links should be helpful:
https://www.chameleonforums.com/everyone-who-knows-you-cant-keep-chameleons-glass-31937/
http://www.chameleonnews.com/10JulAndersonGlass.html
http://www.chameleonnews.com/10JulManchen.html
Chris
know it all newbies.. good luck to you
