I've created unlimited categories feature some time ago, but you should be aware of some facts first:
- there are several methods available to create parent-child structure and I've chosen the simplest and the smallest one (recursive function)
- drawback of that approach was slower routine (and the whole engine as well)
, especially in situations when there is level 4 child applied or more
- other changes to the core includes new navigation system, breadcrumbs, category management, article management (plus 2-3 new functions to patch it all together)
- mod_rewrite behavior is untouched; link appearance doesn't follow parent-child structureyou don't get this kind of structure
the old appearance is preserved instead
because htaccess recognizes all subcategories (children) as category. I'm aware of potential SEO issues here, but another recoding (of the same scale as unlimited categories) would require substantial amount of time.