I was doing something similar to this so it makes browsing categories rather easy, the trick of this which I'm not sure if you've gotten a php file to do such, but in theory, you could create a php file that loops over the categories tables and the php file returns an xml doc for the categories, this was the part I was having the most difficulties on as, looping over every cat1/subcat1/subcat2 and making sure it all nests properly for the xml so the structure is the same, is rather combersome. If you've found a way to do this let me know, as its one thing I'm still working on to this day.
This could make the flash movie dynamic with the admin so everytime a new category is added or current categories are edited/deleted, the flash movie is auto updated, since its loading xml from the php file thats quering the categories table in mysql.
Anyhow, looks good though
