olmekki: Haskell is Turing-complete, and there are no limits to what one can do in one's xmonad.hs. So all that is possible. Whether it's easy I couldn't tell you without you translating it into xmonad terms.
oelmekki @SamC : You're right, i made a too big shortcut. Awesome is derived from dwm which in turn was "extract" from wmii as a rewrite when the main dev thought it has really too much features. That reminds me it was the main reason why i don't switched to awesome when it got published, even if I really appreciated to see the "features are not crimes" philosophy on its homepage :)
@gwern : ok, thanks to pointing it. I read a bit of the xmonad source code, and it doesn't look like any language I know. A good reason to give it a try, actually, if I find enough time.
"I got hit by the exponential merge bug in Darcs (since fixed?)..."
Yes, in Darcs 2 (just recently released). It's a very solid release, but I can't speak to whether it would be more satisfactory as far as 'going back in time'.
@gwern : ok, thanks to pointing it. I read a bit of the xmonad source code, and it doesn't look like any language I know. A good reason to give it a try, actually, if I find enough time.