A friend of mine from southern california was keeping a community tank that had a situation much like this taking place.
Within the equivalent of, Id say, a 50-75 gallon aquarium turned to maximize height (it was a custom built cage, but was about that volume) he had approx. 3 pacific tree frogs (wc), a whites tree frog, a gold(?) tree frog, a madagas. day gecko (approx. 3-4" ) , a bumblebee poison dart frog, 2 anoles and, most important here, he also had an adult golden gecko (decent sized) and a veiled that was approximately the same size as the golden. He HAD designed it quite well, and it had one of the best gradients Ive ever seen in a cage (both in terms of humidity, temperature, and arboreal/terrestrial ratio).
While I found this setup irresponsible at best, he enjoyed it and i didnt want to make an issue of the matter. From what he told me, and from what I saw for that matter, they all seemed to get along quite well. The biggest problem he claimed to have was that the tree frogs had a tendency to, from time to time, bunch together near the vieled when it would go to sleep (something it apperantly didnt appreciate). Even so, the cham would simply open its eyes, stand up or move slightly, and all the frogs would leap away and stay away from it- we guessed they were trying to make use of the cham's slightly higher body temp and were surprised when their 'warm rock' started moving.
The geckos and the chameleon never had any sort of problems, though I would like to note something- not all species follow a 100% set time schedule. For example, I have a number of pictus geckos which are primarily nocturnal- yet, due to my houses location, there are often times when I come home and find my geckos active during daylight hours; especially during rainy/dim weather. As such, its not really 'safe' to assume that a supposedly nocturnal species will get along with a supposedly diurnal species on the basis that they have different sleep patterns.
Whatever the case, in the long run, the chameleon ended up drowning due to a design flaw in the water feature (had large flat rocks coming from the water, which the cham liked to sit on; yet could only barely hold onto). Over a span of about 1.5-2 years, I was never told of nor witnessed any sort of aggression within that cage between the captives. While I understand that it still likely caused them some stress- they gained size, were feeding well and showed no signs of illness or stress. During that time, he had successful breeding of both the anoles and the pacifics.
For all intensive purposes, its something you SHOULD avoid.
But, if youre really, REALLY cramped for space/money; it can be accomplished with careful cage design. Using visual barriers and different feeding locations, I think you could manage something like this- at least for a little while.
