the ball has been crossed with the short tail making superballs which have then been bred back to a ball making mongrels. roussis sells them. i haven't herd of anyone doing a blood ball cross.
i think the super dwarf X ball would work if the blood ball works. full adult bloods are pretty big so???
if you are into hybrids there is a forum for them called hybridhaven.net. its kinda cool but there is not alot of activity. the best hybrid IMO is the carphondroXGTP. they look amazing!