I have seen several wallpapers for Ubuntu with the black wood background, and LOVE the look, and I decided I had to have one for my Gentoo system.
LINK TO MY EMERALD THEME I MADE FOR THIS WALLPAPER:
Sources for artwork used to create this wallpaper:
And also used the gentoo icon from the "start-here" icon pack here on gnome-look.org at: http://gnome-look.org/content/show.php/Token+start-here+collection?content=124975
Enjoy! Hope you like it! This is my first submission on gnome-look, comment! Lemme know what you think, and taking requests for other projects as well, not limited to wallpapers.