While Epic Mickey can certainly be used as an example of transmedia development, I'd argue that the process only got it half right since there doesn't appear to be an integrated marketing plan in effect.
While Twitter has only become even more valuable since then as a professional networking tool, I still look to blogs for deeper engagement, and subscribe to feeds of blogs that offer real value.
Part collectible card game, part treasure hunt, augmented with an immersive online community, Perplex City offers a number of interesting takeaways for anyone wrestling with how and where audience development and transmedia intersect.
My fantasy publisher would follow a pretty simple equation: Tor.com + Runes of Gallidon + Book View Cafe + Cursor = Awesome!
"From the Director of 300 and Watchmen" isn't an ideal tagline for a PG-rated movie aimed at kids.
Ask 5 people what they think transmedia is and you'll get 10 different answers, all with pretty sound reasoning, most likely based on the industry they work in.
And by independence, I mean making a sustainable living, not just self-publishing your book via Amazon or Lulu or Smashwords and declaring yourself an "indie".