I use three different types of faunariums in sizes from about 10 to 20 litres and one home made 20+ litre glass terrarium. I've tested a few home-made plastic storage box enclosures, in sizes from 15 to 70 litres. I didn't like the plastic boxes that much, you can't take good pictures through them.
I'm always considering making juvie enclosures, but I always realize how good the faunariums are. They could keep the humidity a bit better, though.