Well. InSearchOf isn't working on it anymore, and I never did get my environment set up, so if you want to pick up dev work (with Sash, who has been busy according to the SVN repo), you might want to get in contact on SF/wherever with either InSearchOf or Sash (good luck there).
I'd also argue that Xfce isn't so lightweight (12.5% of my Nokia N810's RAM was taken up for EACH widget (clock, window list, etc.) that was added to the toolbar. That would be 25% of the Z's RAM ). Just something to think about...
My $0.02.