PAX Prime runs from August 29 to September 1, 2014. There will be a few devs there at the Bioware Base.

From the Xbox News page:

Dragon Age: Inquisition

Bioware’s biggest and most expansive RPG, Dragon Age Inquisition, has a brand new demo, ready for hands on, exclusively at the MSFT booth! Meet our producers, get your burning questions answered and be the first to play the new content.