My Curly X Arab is gaited; she has what some Curly enthusiasts call the "Curly Shuffle" which about 10% of the breed have. My mare hasnt been tested, but I had read it up in a Horse Illustrated magazine once when they had an article on the breed. Yes, some of the Curly's gaits come from the Fox Trotters, but other's have been influenced by the Appaloosas. That breed was a big help at helping the Curly breed become what it is today. I think they call it the Indian Shuffle when an Appaloosa is gaited, but I could be wrong.
My mare's shuffle is between her flat walk and her trot and it goes at about five miles an hour. Her extended trot may be influenced by her gaiting, which is about 18 mph. Her canter, however, is only 8 mph. Her gait is very ground covering and even people that arent experienced with horse's notice that "she moves differently." You can definantly tell. Have you gone out to ride the horse that you are interested in?
Shaneequah, 1998 gaited Bashkir CurlyxArab mare
Treyue, 1999 3-gaited Icelandic gelding
Loki, 2001-2015 Icelandic gelding