The only problem with the Sheens is unlike say Dark Space,which Monte owns, the Sheens are owned by WoTC as they appeared as official goodies in Dragon.
I agree that those two articles were dripping with flavor and useful information and made more than a side quest or two in several of my campaigns. I found them useful as both source of wonder, horror, and long term antagonist and while I didn't think the follow up article was as good, it still provided a wealth of cool ideas, something Bruce does with most of his products.
I'm looking over the Dark Plea from it's two product apperances as something to perhaps use as an 'ultimate' evil or something along those lines. A vastly powerful force that doesn't really make itself known.
Monte's message boards would be a good place for this as would a letter to Dragon Magazine.
Perhaps even to Dungeon and make it a Polyhedron special like Incursaion or Spelljammer?