Recently I've been talking up various ideas for pluggable subsystems in Drupal in IRC and the other usual haunts. Ideas have been percolating in my head, but so far I have been remiss in actually writing them down. Yesterday, however, I had an epiphany to solve the primary issue I was trying to work out, so I present a hopefully workable RFC (for real, not IETF version) for pluggable subsystems in Drupal.
I am posting this over to Planet PHP as well to invite commentary from those who aren't already embedded in the Drupal mindset. :-)