Sorry for the necromantic post, but I wanted to answer Baker's request of hearing ideas for future Q&As.
This may be a dead horse, but I wouldn't mind a more precise description of what Sharn looks like from the inside out. It is something I struggle with to this day despite Sharn being my favorite piece of content in a RPG. Things conflict in weird ways; novels, images, source books, popular thought, etc all have their own ideas it seems. Something as simple as what it would be like to walk(/fly/etc) from the cogs to the very top of skyway in day would be nice.
But I understand if that may be too tired.
Maybe a fresher topic would be exploring what the big bads think of each other. Which are more likely to ally, which hate each other as much as they would hate, say, the Silver Flame? Is there a pecking order among the "manipulators" in the shadows (since you know, Eberron potentially has a lot of overlap in secret continent-wide evil schemes)? I know you've said that Overlords are the most powerful, so how would these organizations feel about one's release being eminent? Or Xoriat becoming coterminous? So 'n so becoming a death god? You get the idea.
Also Baker, I just want to say these Q&As make my day and I'm always excited to see them. Thanks for continuing them.