When I got back into orchids after being away for many years, I ended up going for tiny ones. At home, I have more than 20 plants in a 30 gallon terrarium.
I have a little greenhouse space, too. That's where I'm growing about 20 minicats. I won't have the greenhouse space forever - they'll end up under lights in the winter and outside in a shade box in the summer. Ain't it fun?