It seems that Openbox doesn’t really have an official logo that is used universally with distros, except the one they use themselves over here:
http://openbox.org/wiki/Main_Page
And since we are going to add Openbox very soon to the ISO, perhaps some of you are willing to create one for us. Openbox is going to be a community edition, so there’s creative freedom.
(In case you are wondering about the commonly used box image, most distros use slightly different versions of that one, so I don’t want to get in an unnecessary discussion with creators about it. )