My b2evolution Version: Not Entered

I plan on using b2e on a site where I need to associate each blog to both a location and a topic. I can obviously set these all up as categories, but my concern is that I will then have over 100 categories. That will make the "write" page very long and the blog page long as well. I need to be able to create sub-set pages (say for a specific location) that list just the entries for that location (category). I assume that is as easy as fltering by a category.

Is there a way to manage my categories better than having such a long list? Could I build a plugin that would display the categories in a drop-down as opposed to a bullet list?

Since I am associating with two different types (locaitons and topics) should I still use categories for both or build a plugin that adds a second type of association?

Any suggestions on the best way to pull this off are appreciated! Thanks.