I have the Abena bodystockings, I think they are similar to the ones from XP Medical, anyway mine are in size medium and they fit perfectly.
For the record I'm 6'1 tall and normal build.
For Comparison I bought a few bodys from Babypants since they are the only one who makes them with plastic snaps, which I need when on business trips in order to stay stealth through security etc. However due to the sizing of the bodys from Babypants, I ordered them in size XS, and still they are not as supportive as the Abena ones and they are by far more wide in the crotch.
For the Abena bodys if you're interested I get mine from Sue Ryder for life in the UK, the price are reasonable....at least when comparing with XP medical.
http://www.sueryderforlife.co.uk/incont ... cking.html