I don't know why I have been thinking of this but.. here we go!
Rainbow Dash: 5'2 Pinkie Pie: 5'3 Twilight Sparkle: 5'5 Rarity: 5'6 Fluttershy: 5'9 Applejack: 5'10
Rainbow and Pinkie being short... Twilight and Rarity being average... Fluttershy and Applejack being tall.
This is just how I kind of see them based on their personalities and even how they are drawn..
Thoughts?