Here is a mat designed to help you perfect your handstands. The Tumbl Trak Handstand Homework Mat can be easily attached to any door with slide-on clips and velcro straps. This is a reversible mat, with a cartwheel side while the other has a 6ft long and 4-inch wide beam stripe.
This handstand mat is foldable, so you can get it out of your way. You can find out more about it here.