Categories in Blogger: Rolling my own

So what I haven't considered yet -- but I guess it's about time -- is writing my own non-bookmarklet solution to this problem. A bookmarklet ain't gonna pump files onto my server, and that's really what I need here. After each posting is published, I can ping a script on subRes to create category-specific html views. What will I need to do?

1. read the posting (either the xhtml or atom xml) and determine which tags are present (this should probably use Technorati's a rel="" attribute),
2. for each tag, find the existing or create a new category html view (at path ./tags/tagname/index.html),
3. profit create an atom.xml or rss.xml or both under the same path.

Seems simple enough.