I gave these a try again after listening to Eric Helms talk about them on the 3DMJ podcost, and holy hell these lit up my lats. Just wanted to mention these in case you're looking for a back hypertrophy exercise that hits the lats really well.

I set up letting at around a 30 degree angle from a high pulley and brace myself on something (a box in my case). I let the weight pull my arm up and across my body, get a good stretch in my lat, then pull my elbow down to my hip.

IIRC the cross body variation is done because it increases the stretch on the lats.