Why did they make those penny farthings so dang tall? I know it's a bit more efficient to have a larger wheel but in the interest of convenience & safety I think I'd rather ride one which isn't so dang tall.
Oh and in regards to unicycles, I think I read or heard somewhere that the taller the unicycle, the easier it is to balance. Which makes sense because it's easier to balance something that's fairly long on your hand than it is to balance something which is a lot shorter.