If you got color and a colt, then gelded it, you could register under a hardship clause. Arab is an acceptable cross to the Appaloosa Horse Club but not mustang. You'd think appaloosas originally came from some high dollar breed from Europe instead of spanish mustangs the way they act :)
Oh - I didn't realize they wouldn't allow that cross... I thought since Arabs and QHs were allowed, they'd allow other crosses as long as it came out colored.
Well, crum :~)