Personally, I've always been partial to Chaos's mist fabrial theory. There hasn't been any new info to disprove this, has there? Your harmonium theory's also quite interesting, though I'd like to know more.
Apologies if any of my questions were already answered in the thread. Does your harmonium access identical powers to those associated with Allomancers? If so, how exactly is it targeted? Say, if I touch a bar of harmonium against some steel or zinc. How does the metal decide what's getting pushed, or what emotions are getting Rioted? What if I try to activate duralumin, or nicrosil? What about Atium, malatium, gold, and electrum?