I'd love to see this available to buy as a T-shirt: [1] and these posters [2] (here, in Hungary we have plans to do both)
btw Wikimedia Hungary had some own merchandise too [3]
[1] http://commons.wikimedia.org/wiki/File:Wikipedia_-_T-shirt.jpg [2] http://outreach.wikimedia.org/wiki/Bookshelf#Posters [3] http://commons.wikimedia.org/wiki/Category:Wikimedia_Hungary_merchandise
cheers, Balázs