Here are all the Ball hybrids I've come across:
Black Blood Ball (Sumatran Short-Tail Python x Ball Python)
Super Ball (Borneo Short-Tail Python x Ball Python)
F2 Super Ball (Super Ball x Super Ball)
Mongrel Ball (Super Ball x Ball Python)
Wall (Woma Python x Ball Python)
Carpall (Jungle Carpet Python x Ball Python)
Spider Carpall's can be seen here:
http://www.faunaclassifieds.com/foru...d.php?t=179410
Burmball (Burmese Python x Ball Python)
Angry Ball (Angolan Python x Ball Python)
Hidden Gene Woma Angry Ball (Angolan Python x HG Woma Ball Python)
Reticulated Python x Ball Python
Golden Child Reticulated Python x Ball Python
I am willing to bet a GTP x Ball cross could be done if you can manage to get them to breed. Since one is arboreal and one is terrestrial, that might be a challenge. I would expect the genes to do fine together though since so many python hybrids have been made regardless of their genus.