I'm still interested in this plugin, but I have another major project at the moment which is taking up all of my time.
What I would want to get solved first is the tags plugin. mystral-kk.net has one but it has a number of bugs and I would like to see a few more features in it (tags for staticpages for one). Joe also has an unfinished tags plugin which would work out if it gets released for Geeklog.
I would also build in an api into the related plugin that other plugins could take advantage of and be included in the related list.
One of the Geeklog Core Developers.