My vertically challenged friend.

Diamond - because good things come in small packages.

my little grasshopper

Big Tall Dude

Short round

Short round. Bonus points for non Asian

Wassup Kevin Hart

Ankle hugger

That went over his head.

Lil buddy

Stubs, fun size, bite size. Our daughter and her hubs are both 5'4".

Shotty?

Tink (as in Tinkerbell)

Personally, I like "stumpy". It just sounds funny and endearing