I did play with evilwm some more -- specifically, compiling it and setting it up in X on the mac. Unfortunately, the combination of three button emulation with modifier keys to drag things around and resize them does not work so well. I'm not actually sure of the issue, but I did hack the code to report mouse events, and found that that evilwm is never getting the 'middle click' event when it can be interpreted as a paste event. (So for xclock, it is getting through, but for xedit, where it can be interpreted as a paste, it's not.)
This could well be some kind of X configuration thing, or something else: Certainly OS X does not create the cleanest X config in the world. But I also don't have a lot of goal of futzing with X.
Oh, and booting to Ubuntu on the Macbook failed -- never even got past the loading, the progress meter just froze. I let it sit for 20 minutes, then gave up. I'm hopeful that I can eventually get most of what I need out of OS X -- possibly I'll still need to upgrade to Leopard to get some of it, since in Leopard, X is X.org instead of X.