I took Daniel Naber's tree perl script (tree.pl)* and by changing ten
lines converted it from output of XHTML to OPML instead. This
provides input to Danny Goodman's OPML navigation javascript widget.**

Works great for me. Let me know if this is something of interest.

* Daniel Naber, General Public License, <http://www.danielnaber.de/tree/>.

** "Collapsable XML Menus" recipe 10.11 on page 307 of his "JS&DHTML
COOKBOOK (O'Reilly & Associates, Paperback, Published April 2003, 520
pages, isbn:0596004672, for sale $40 list $25 bookpool
<http://www.oreilly.com/catalog/jvdhtmlckbk/>.

Cheers
:Monty