[xmonad] Making utility windows "dock like"

[Gregory Maxwell]

I've been using xmonad with great success with my thinkpad x61 tablet.
Although xmonad is so keyboard focused it still works quite well
without one— so long as the compromise of a panel desktop switcher is
used (I'm using gnome-panel).

One issue I haven't solved yet is cellwriter
(http://risujin.org/cellwriter/).  According to xprop cellwriter is a
"utility window", not a dock, and doesn't provide the struts field,
even when it is set to dock mode.  As a result, when I unhide it using
the notification icon it pops up as a float in the middle of my
screen.

What I'd like to do is treat it as a dock: Accept the size it assumes,
force it to bottom of the screen (just above my existing panel), and
prevent anything from overlapping it or it from overlapping anything
(shrinking the tiled area as a result). I expect that other people
might find the same kind of behavior useful for things like
calculators, but perhaps not— since it wouldn't be important to have a
calculator on all workspaces. :)

Can someone point me to some starting points on how I can get it to
behave this way?