I'm 5'2" (with very short legs) and ride a 14h Haflinger gelding (a real stout, drafty boy), my hubby is 5'10" and rides a 15.1h Belgian/Haffie cross. We both primarily trail ride western.
As a teen/young adult, I rode a 16.2h Anglo Arab. Mounting on the trail without assistance was a real challenge. I now really enjoy the little guy...except for when the creek crossings are high in the spring and my little cousin informs me that me and my "pony" may not make it across (we do, but I do have to take my feet out of the stirrups)