Anthony Caponetto has a great Carpet care sheet that goes over cage sizes.
http://www.acreptiles.com/main/index...=81&Itemid=140
AdultsAdult Jungle carpets and Irian Jaya carpets should be kept in a cage with a minimum of 4-6 square feet of floor space, such as a 2'x2' or a 3' x 2' cage. As a rule of thumb for pythons in general, some keepers say that one square foot of floor space per foot in length is optimal, but I think slightly less than one square foot is fine for carpets, due to their slim build.
Cage height is a subjective subject! What's best for your snakes has a great deal to do with the temperature and humidity in the room that the cages are in. My carpet rooms drop into the low 70's in the dead of winter, so cages any more than about 15" high become problematic, as the taller the cage is, the more become difficult to maintain a proper heat gradient and proper humidity. Recently I have had great success breeding carpets in rack systems that house tubs 6.5" to 8.5" high, and the snakes do not appear to be cramped or unhappy in any way. In fact some of the more shy carpets I own have actually done better after being moved to a smaller space.