是否有一个类似于drupal分类系统的php类？

I'm interested in a system that basically, provide tags organized in categories and subcategories (and, why not, sub-subcategories).

Something like:

SMARTPHONE (category)
    Apple iPhone (subcategory)
        Apple iPhone 3G (tag)
        Apple iPhone 3Gs (tag)
        Apple iPhone 4G (tag)

I was interested to use the drupal taxonomy system to do this. I'm working with a custom cms, zend-based.

What do you suggest me to do? Do you think i can somehow extract something useful from the drupal taxonomy or should i do it all myself? Or maybe there simply is a zend class (i don't know) that does all this?

Thank you a lot =)