Hydroponics
Perhaps some of you aren't familiar with the mutitude of different hydroponic methods there are. One in particular that would suite this need perfectly is called a DWC ( Deep Water Culture ) bubbler bucket. Basically the water is fully enclosed in a 5 gallon bucket with a lid with a netpot filled with grow medium ( Hydroton, Marbles, Etc. ) The nutrient are added through the hydroton with the usual 2+ quarts a day a fast growing plant would demand.
The best light to suite both the plant and the animal would probably be Mercury Vapor or Metal Halide, I know for a fact MH has a better UVB output then High Pressure Sodium, while not as conductive to bloom for the plant as HPS, it would do more for the animal. Mercury Vapor can support a plant, and obviously fufills the needs of the animal.
I can't think of too many problems using this system, the water is fully enclosed and unable to be reached by the animal or its food. Plant growth in these bubbler buckets can be absurd to say the least, Pending on light wattage heat could be a slight issue, but im sure you could cut back the wattage for a slower growing, more spindly plant, which would probably both be more conductive to keeping the Cham, rather then trying to harvest bulk from a plant.
My only further concern would be the edibility of the plants, generally before harvest the plant is flushed for 2-3 weeks with pure water and no nutrients to flush the nutes out of the plant, I assume if you used a lighter nute mixture you could grow the plant more slowly, and at the same time make it safer to be eaten by the animal.
Furthermore Low stress training is a method used to keep larger plants manageable in a smaller area, and would create many more horizontal branches for chameleon use.
This is a simple diagram of the system
Here * Work Safe *
These bubbler buckets are a snap to build, they require a fishpump, airstone, water level checking tube, bucket, netpot, and grow medium. All easily aquired.
Be advised in searching any of this material or terminology on google, that you will be looking at tons of information on growing illegal plant life, but the information carries over to any plant that is managable in a hydroponic setup
Joel Letcher