I just ordered two!

They are cheaper if you buy them direct from the master North America wholesaler, "EarthEasy". $19.95 each, $2.95 shipping for one, $3.15 shipping for two (to my Colorado address).

http://eartheasy.com/lifestraw

Buried down on that webpage is a blurb that says to send email to info@eartheasy.com if you want to be notified when the larger "LifeStraw Family" is available for purchase, expected sometime mid-2012.