Well, rainbird does have an online store front:
http://store.rainbird.com/shopexd.asp?id=396&bc=no
But at almost $20 a pop, seems like there's cheaper alternatives.
As an example, look at this price page from this forum's sponser:
http://www.sprinklerwarehouse.com/Rain-Bird-5000-Plus-Rotors-s/354.htm
About $10 each. So what is really the difference between the SA and these?