Honestly, I'd probably turn a tall tank like that into some kind of paludarium for a bunch of frogs and/or geckos, or even a pair of chinese water dragons.
A big brackish tank might be nice, too. You can fill it with scats, puffers, gobys, etc.
Ok beardies and chinese water dragons get way too big for this tank. Beardie gets about two foot long and a chinese gets almost three. I would fill the tank like 3/4 of the way up and fill the top with a couple branches and get an archer fish. Then you could put some crix on the branches and watch them shoot them off.