I once rode a donkey that was probably 11 -12 hands (same as our pony). I know someone who breeds donkeys and people bigger than me ride her donkeys. I weigh 52kg and her donkeys probably average 11 or so hands.
When I bestride him, I soar, I am a hawk: he trots the air; the earth sings when he touches it; the basest horn of his hoof is more musical than the pipe of Hermes. ~William Shakespeare