I don't know if this has been available elsewhere, but the Leonardo is finally for sale at Makershed.com.
Lets hope the Due is on its heels.
Has been out for a while now:
I saw them overpriced at Radio Shack, ordered online from nkcelectronics.com, and received it over a week ago.
heh every time I am in radio shack I make a stink, OH gee I would buy this propeller if it wasn't 10 bucks cheaper on their website har har har