I now have a test installation of Drupal CVS top-of-tree installed at home, and have gotten a copy of the FOB database into it, and can work with it. I've even included a version of my custom hacks for my blog's page headers. I'll need to redo it before submitting patches, but this was a key step. I also got weblogger.el to work…
In an earlier comment on FOB, Josh reminded me that if I want to avoid composing online, I can get a blog client, of which there are a plethora, and use XML RPC to upload completed entries. Sadly, the version of Drupal currently running FOB is too stale; the XML RPC is both broken and contains a bad security hole. Thus, I finally had sufficient incentive to complete a test installation with an eye toward bringing up latest CVS of Drupal for the actual FOB.
It was a pain to get Drupal up. The database from FOB mostly just loaded in. Then I spent a lot of time struggling with weblogger.el. I fixed one bug, and got everything configured a bit. It seems to work. Hilarious.
Attached are the files I'm using, if anyone wants them. I doubt it.