Fragfutter's Uncollapsed Categories Tree is still at his site, but you have to look very carefully to find it (page 2 of the "Software" category). Here is a direct link to the correct location (as of February 2, 2014):
http://www.held-im-ruhestand.de/soft...art-categories

Alternately, the mod files are available bundled as an option in Categories Dressing in Plugins here.