Well, you can still have a display tank. Walmart sells 10 gal for $10. Look on craigs list in your area for a nice one. Im sure you can find something. Its just that a 55gal sems too big even for an adult female. I temporarily had my largest female (she was 2500g) in a 40gal breeder reptile tank and it seemed too big for her even.
I would look for maybe a 20/30gal. The 29 gal are tall and narrow so anything other than that would be easier to maintain.
Do you know anyone who is handy with wordworking tools and saws? You could always have one made with melamine or plastic with plexiglass doors. I would stay away from wood though. It could be made more short and long for a nice display.