heh I go away for a little bit and ya add a dozen posts when I'm not looking...
Generally (as far as I can tell) 5'7" is the minimum height because thats often the minimum height for "fit models" who work with designers to see if outfits "work" atleast thats the requirement for the small local company down the road from me ...Abercrombie and Fitch
Often "modeling schools" will take people shorter because they're getting money to do so from the student. I saw one model advice colume recommending that you send a short ugly friend in first to see if they get accepted!!

I've never met an agency model who was shorter than 5'9" though I've only known 3...
My hope is to get peiople who atleast have the potential to be regularly working models because of the interpersonal networking side of it so I be taken as being more legitimate when I'm done.