vocabulary

I've been trying to wrap my head around this for a while and I'm running into a roadblock in terms of providing good usability to community members vs. correct information architecture. As an example, let's say I'm running a website about plants, and visitors can add articles about different plants. This is just a crude example to help understand the problem. When a visitor goes to create a new article, they can categorize it as follows:

Plant Part
- Color
-- Produce

I'm working on a D5 site (yes, unfortunately!) where we use taxonomy to create a "poor-man's-epublish" - basically a view of newsletter issues and articles under them. We have a vocabulary for "Newsletter issue" and just tag article nodes with the term of the issue, like "Fall 2008." Since there are other vocabularies on those nodes we're using the primary_term module to make the newletter issue the primary term.

It's all working great except for sorting: primary_term.module only implements views sorting by term id - it ignores the term weight:

FOAF, DC, SIOC, SKOS are famous vocabularies commonly used in the Semantic Web. Many other custom vocabularies exist and are created everyday. Vocabularies play an important role in the Semantic Web as they enable interoperability across various RDF data sources, and are used by RDF publisher and consumers who refer to them in their data.

Hello Everyone,
Is there a way (a view, an existing module, a swell hack), to limit the display of a vocabulary in a node editor?
For example:

Countries (Vocabulary)
- Africa
   - Kenya
   - South Africa
- Asia
   - Japan
   - Thailand