Hey, Dave, I have to agree that Lisa Williams is doing a fantastic job...but h2otown.info is actually a Bryght-hosted Drupal site. Lisa's Wordpress blog is here.
I said a few things about Drupal supporting OPML a while back. No editing support yet: I know I'm still trying to wrap my mind around what the best way to do this is. I've tried the OPML Editor, but it's too stuck in Mac OS System 7 for me to use...too many different "funky" bits, no proper integration into OS X, etc. That, and I hate the lack of support for permalinks that are full URLs. But anyway, less complaining unless I'm actually going to do something about fixing it -- this is open source, after all.
So, I think the best fit between OPML and Drupal is the book module -- which consists of arbitrary content types (e.g. blog posts, images, events, etc.) organized in a hierarchical outline. You can have multiple "root" pages, each of which would map to one OPML document, I think. Djun Kim is already tinkering with general XML import/export, as well as DocBook export, so OPML would likely fit in there.
For round trip editing/live editing, I think we can just implement some XML-RPC hooks on the Drupal side. But I'm really stuck on the client: I want an OS X native OPML editor...basically, an XML-RPC aware version of Omni Outliner. Dave, is there documentation on the protocol used somewhere? The real time one, I mean.
And at some point we'll see something for the Windows crowd from Dan's Focus outliner.