I've been building small cylindrical terrariums recently based off of designs I've seen here and elsewhere on the web. Not a full sized vivarium and no frogs, but I thought you guys might be interested in some pictures!
This one is based on a glass candle holder from Ikea and measures about 11 inches high by 5.5 inches wide. The case/lid is made from 1/32 polycarbonate bolted together in the back. Plant wise, all the moss and the vine thats growing up from the base were collected in the woods near my parents house in Connecticut. I live in Los Angeles, so I shipped the materials over here since we dont have much in the way of moss filled woods. Other than that I just added a small cutting of Peperomia Eburnea which hasnt had any new growth but has rooted and seems so be doing well. All the other little plants sprouted from the moss! I've also had a lot of interesting fungal growth on the back of the piece of grape vine!