I'm thinking about something similar for a new site.
I haven't written any code right now.
But i have some ideas about that. In
modules/xanthia/plugins/outputfilter.shorturls.php
you have to check if there are pagesetter links.
For each link to a publication fetch the value of the categorie field and its subcategories.
Rebuild the link in a way you like and choose a different file extension then for the other shorturls.
Somewhere in this link you have to put the tid and pid, so that you can use it in the htaccess file.
for example:
www.example.com/PhotoShop/Tutorial-5-8.phtml
for tid=5 and pid=8
So you can check in the htaccess file for something like that:
I stopped thinking about that, because in 0.8 the shorturls seem to be in a similar way.