In the event that this is not possible, does anyone know of an
alternative that might already exist? Googling hasn't turned up
anything, but I can't imagine that nobody's ever needed such a beast
before.
You could try writing your own File/Directory Dialog, and it probably
wouldn't be as hard as it sounds. The "wxPython In Action" book (Rappin
and Dunn) specifically points out that a TreeCtrl/TreeListCtrl could be
used to implement a file browser. Basically, by using
SetItemHasChildren, and
wx.EVT_TREE_ITEM_EXPANDED/wx.EVT_TREE_ITEM_COLLAPSED events you can
build/destroy the tree dynamically as the user navigates it without
parsing the entire filesystem first.
You also might be able to do something with the MCVtree, the wxPython
Demo shows an example of a "Late-bound" MCVtree that also does not
retrieve file system data until the user expands it.
With either option it's almost trivial to set the root of the tree
anywhere in the file system and then allow browse downward from there,
then it's just up to you to write the boring stuff...
-Greg