The Mei Tai carrier can quite easily be used as a hip carrier (in addition to it being great at back and front carries). My guess is that this works best after baby gets substantial head control-- maybe around 5 months or so. The model in these photos is 15 months old.
To do this, first tie the waist. Bring the carrier front to the hip and hold the child there (through the carrier).
Then pull one top strap over the shoulder and the other around the body (at the top of your ribs). Cross behind baby's back and tie these, either behind your back or behind baby.