And interestingly enough, I seem to have gotten all exercised about the
*least interesting* aspect of the cross-device mv problem.

If the target of the symbolic link doesn't exist, you can't move the symlink
itself.

If the target of the symbolic link DOES exist, is a regular file, and is 
readable, you "move" the symlink by creating an ordinary file containing
the contents of the target file!

All that misbehavior from just one missing character.  ;-)