The mission: Namecoin is a peer-to-peer generic name/value datastore system based on Bitcoin technology.
There is no slogan yet afaik.
It might resemble the bitcoin logo: https://bitcointalk.org/?topic=1756.0
Open to other suggestions, too.
It might use this symbol: ℕ http://dot-bit.org/forum/viewtopic.php?f=2&t=483
Necessary for full bounty:
* vector format readable with Inkscape (.pdf, .eps, .svg)
* namecoin logo (maybe in a blue complementary to bitcoin?) plus writing
* me/the crowd linking it
Optional:
* a button
Not necessary:
* gold coin
* hearts
* cats
edit:
SUMMARY / my personal favorites