Thanks for all the input. The original poster (me) is still reading this thread.
As for Rick/Camel/Indah's suggestion of Gangga or Siladen Resorts, I checked out Siladen's web site. They emphasize Bunaken for diving and don't mention Lembeh if they indeed make trips there. Looks luxurious, though. There are more guest comments about the food, service and scenery than about diving, and it mentions people doing their Open Water there. I would say that Siladen looks nice but is not for us. We may be looking for a little luxury on this trip, but we're definitely focused on diving and want to be at a resort that's dedicated to diving.