Edit: Unfortunately, the images originally included in this post are gone, because of hosting problems in late 2009. My apologies.
Out of curiosity, I went ahead and made an Openbox mockup of Xubuntu too. It’s all right, but I think the novelty of a pseudo-Gnome desktop made this one a little anticlimactic.
It does look a little better, in that Xubuntu’s single Applications menu button has an icon, and it doesn’t need Places or System menus. That Openbox theme isn’t very close, but I didn’t care to spend any more time on it.
System performance is about the same as the Gnome version, which makes sense since they’re both running the same profile.
Ain’t no way I’m doing a Kubuntu version. That one is all yours.