I just released a simple hack that allows VBulletin to display 2nd-level subcategories (i.e., a 3-level forum listing) on a forum's home page.
[Update] Collapsing/uncollapsing of parent and child categories does *not* work as expected. My initial fix only worked for 2nd level categories that only had a single forum. I've reverted the templates so that they now work with multiple 3rd level forums but collapsing a parent category does not collapse the children alongside. It looks like I need to dig deeper into the code to fix that.
Please read the notes on the thread at Vbulletin.org for background and installation information.
Please note: The hack is available for download at VBulletin.org for registered VBulletin owners only (their policy, not mine -- but it *does* make sense!)
I wasn't able to attach the screenshot (the upload form kept giving me errors) at VBulletin.org so I've added it here instead (click on the thumbnail to see full version.)
The VBulletin 3 Level Forum Home Hack article by Aral Balkan, unless otherwise expressly stated, is licensed under a Creative Commons Attribution-Noncommercial 2.0 UK: England License.
Thanks,