DFEY had a logo competition and all of the designs are CC-Zero licenced.
Some of them are specific to DFEY but some of them you might be able to
customise."
I think that doing that would be VERY wrong. A logo is something that represent an organization and so, every elements are there for a reason. Creating a GNU Generation logo is something that can't be copyed and modyfied, it has to be created from 0.
I'll ad the list to the wiki page as soon as possible.