I took my first lessons as a 7 yr old on 16 hand Saddlebreds and (slightly shorter) Arabs.  They were all great and very tolerant.  The lesson teacher had to spell the names of the gaits or they would pick them up before I had a chance to queue them.  My legs didn't even extend past the saddleseat saddle flaps, but they would go right into a trot or a canter for me with minimal fuss.  They were all saints and the reason that Saddlebreds are still my favorite breed, and the reason I currently own one.  Those retired showhorse Saddlebreds can be very tolerant and laid back, yet sensitive enough to respond to little kid or beginner aids without having to kick, kick, kick.  I think Saddlebreds tend to get a bad rap.  The snort and blow is largely just for show, but it comes across very intimidating if you don't know that the show is just that, a show.   

Sammy the Saddlebred