Categorizing blogs (not posts)?

Is there a way, either natively or by plugin, to group blogs into categories in a multisite setup? We have so many blogs now that viewing them in a alphabetized list is no longer helpful.

For instance, if the blogs returned by get_blog_list() each had a value for get_blog_option($blog, ‘blogcategory’), that would do it. Something like that.

Thanks….