A tortoise, blue tongue skink, and a bearded dragon.

[John1982]

Do yourself a favor and save some money. Do it in a 55 gallon with green anoles (diurnal) and house geckos (nocturnal). Keep 5 anoles and 5 house geckos. They both eat bugs and I've actually seen them cohabbed successfully before. You can switch out the house geckos for green tree frogs or something if you can't find house geckos.

This has a much higher chance of success with the limited space you're looking at, skylord0110. As a youngster, I helped my dad maintain a communal 55gallon. He was a 5th grade teacher and this was a setup he would do every year in his class and break it down to release the animals when summer came along. The general setup was a piece of glass that was siliconed on one side to create a water area roughly 12x12x6 inches, the rest of the aquarium land. The land had a short layer of gravel for drainage and then topsoil on top with a couple small tropical plants added for cover/basking. He'd typically stock it with a few local tree frog species, green anoles(limit 1 male, several females is fine), a rough green snake and a few tadpoles in the water area. The key to keeping this setup successfully was everything either being insectivorous, sexually compatible, or not large enough to eat a tank mate.