I'm noticing some strange behavior with my Openbox+ROX+fbpanel setup. In particular, when you restore windows after hiding them with fpanel's "show desktop" button, they come up in a strange way. It's pretty much not acceptable behavior ... So I am back to considering IceWM+ROX and Fluxbox+ROX.
There are a few more things that need to be ironed out with the Fluxbox setup (e.g., getting CPU and net transfer metering setup ... using Conky? Slit-widgets?). I like Fluxbox's aesthetics and aesthetic opportunities better than anything I've seen with IceWM, but I am not convinced as to its usability. I think ultimately some user testing will be needed to determine whether an IceWM or a Fluxbox-based solution will be best.