Request: Folding category list for Write window

I’d like to use categories to classify news sources. I have in mind a 2-level hierarchy made up of country and publication name: something like “US – New York Times”, “China – Asia Times”, etc. Conceivably, this could involve hundreds of entries at the publication name level, and that wouldn’t be manageable given the current Write layout.

Now…Kafkaesqui pointed me to this interesting post about proposed changes in WP 1.6. I see that there’s a chance we’ll get some cool, collapsing Write doodads which would allow all fields to be accessible in much less space. How about applying the same principle to a collapsible categories hierarchy?

I’d love to be able to drill down into a large set of categories, instead of only being able to pick from a (long) list!