I'm curious what problems you ran into here. (Also, did you use xmonad from darcs? There is XMonad.Config.Mate which clears up most of the discrepancies between Gnome 2 and Mate, and which I am using with Mint's Mate.) The only one I have noticed is needing to restart mate-panel due to a timing bug which is fixed upstream but not yet released; but that is unrelated to xmonad (it's triggered by VMware guest switching to full resolution after the panel starts).
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