Hi there! I haven't posted for a while but I just went through the "How can I make a terrarium?" idea about 6 months ago for some draculas. I live in SW Colorado at 7000 feet, so very warm and dry in the summer, cold in the winter. Sun-wise and Humidity-wise very similar to Tucson.
What I did was go to the local pet store and buy a used glass 20-gallon aquarium. I got rocks from outside, washed them off really well, and used a combination of flat large rocks and small rocks in the terrarium. The pots and plants sit on the larger rocks, and I pour distilled water to about 1/4 inch over the smaller rocks (and perlite) on the floor of the aquarium. That keeps a lot of humidity in the tank, but not so that the plants are sitting in it. I then went to the auto glass store and had them cut me a piece of acrylic that fits on top of the tank, leaving an inch or so open on one side. Depending on the humidity, I sometimes cover that inch with a gauzy fabric, so that it will keep some humidity in but allow good air circulation. I usually try to spray them once a day just with a bottle sprayer.
For excellent air circulation, I got a computer fan and wired it up to a DC power supply. It sits on top of one of the larger rocks. It is very easy to do, and I am NOT a handy type of person. I don't even know how to download pictures of my terrarium from my camera to the computer (which I have and would do so if I knew how)!
The whole set up gets some later afternoon sun, so usually ranges from 60-80 degrees depending on the clouds, temperature, etc. You don't want it above 80 for these types of plants. With the water in the bottom of the tank, and the fan blowing, my temp has really never gotten above 82, even on very hot days.
Thus far I have added many plants to the mix. I lost one seedling dracula, have 3 dracs that have new growths, and have had multiple blooms on some trichosalpinx, dryadella, restrepia, and pleurothallids, which I just bought in January; as well as new leaves on masdie, zootrophion, and dracula. I have not gotten the dracs to bloom yet -- but hoping they will sometime soon! They look healthy and have some new shoots, but haven't given me any flowers . . .
Anyway, since we're in similar climates, and you, like me, seem to be looking for a small and inexpensive ways to try some cooler-growing flowers -- I did mine for well less than $100 ($10 for aquarium, $20 for acrylic top, $20 for fan, I think about $10 for the DC converter, $2 for distilled water and free rocks! And I only bought about 3-4 plants for about $7/each online initially to see how they woudl do before I added more -- I got 3 dracs and a masdie).
So it works, it's fun, creating an Ecuadorean cloud forest in Southwest Colorado!! Good luck and let me know if you have any questions!
Kristin