Not finding any such pointer, I discovered a clean hack to do what I want.

For those who are interested:

* Add a ComponentListener to the JDesktopPane that detects when it has
been resized.
* Get all of its internal frames via its getAllFrames() method.
* For each of those frames THAT IS AN ICON, tell a grievous lie by
putting the following client property into it:

  "wasIconOnce", "false"

This is a lie.  It clearly WAS an icon once--actually it IS, right at
this very moment when we're looking at it.  But note that it is the
evaluation of this property that causes the DefaultDesktopManager to
decide whether it needs to recompute the location/bounds for the
DesktopIcon.  So we're effectively tricking the DesktopManager into
recomputing the bounds on a resize.  Note that the very first thing that
the DefaultDesktopManager does at line 143 is reset the "wasIconOnce"
property to TRUE, so when we're all done we haven't touched the state of
things at all.
* Call desktopPane.getDesktopManager().iconifyFrame(frameInQuestion);

Works like a charm.  Those who want a marginally less hackish approach
will override the DesktopManager's wasIcon(JInternalFrame) method instead.

Best,
Laird