I had done something that might work for you.
I had used the lower part of terrarium table and close it with wood covered with plastic cover so the humidity wouldn't harm the wood.
On the front side I have used glass sliding doors.
on the bottom I have build a water tray from glass 4" high there are water in it about 3" high and a net cover the water and it used as a base to the Nepenthes pots.
There is small old computer fan work with timer also 2 32W saving energy fluorescent lamps mount to the top of the chamber.
The humidity in this chamber is about 80%.
At my site you can find a quick lesson on building an enclosure. At step 5 instead of putting wood panels on the back and sides staple a big plastic painting drop cloth from home depot to keep the humdiity up (I learned this after I built the one shown on the site). If you can follow the steps (I'm working on another version with better step definitions) you can use the same steps to make any size enclosure you need/want. The one on the site is 48" high x 24" tall x 24" deep. http://the-natural-aquarium.com/48interr.html