The default install uses xsetroot to set the wallpaper:
WALLPAPER="xsetroot -mod 2 2 -bg #666699 -fg #888888"
xorg-x11-7.x doesn't install xsetroot by default.
Add x11-apps/xmessage to the list.
Sorry, I will never touch wmii again.
(In reply to comment #2)
> Sorry, I will never touch wmii again.
Hrm? Why? /me is confused. :)
Anyhow, added both to RDEPEND. Closing bug FIXED, although I would like to know why tove said what he did.