I would be inclined to purchase a cage suitable for a ball python. They really do well with 12" of height and need no more than that given that they are terrestrial snakes.

I have these cages: http://www.reptilebasics.com/2x3-Cag...h-p-16286.html with flex watt and a thermostat to control the flex watt.

Another way to keep ball pythons is in a tub/rack.