The schedule for the 2013 Game Developers Conference indicates that we won't have to wait too much longer to find out more about Bungie's new project, listing a lecture from the acclaimed studio, titled "Brave New World: New Bungie IP" that will discuss the challenges of their momentus new task (via Polygon):

The presentation from design director Joe Staten and art director Christopher Barrett, both of whom are 11-year Bungie veterans, will give attendees "key insights into Bungie's battle-tested design process" and a look at the studio's "world building techniques, from concept to production." Staten and Barrett will also offer a look at the world of Destiny itself, which the studio refers to as "a place where the next ten years of great Bungie adventures will unfold."

It's possible that we'll see a formal reveal before GDC in March, but no other announcements have been made.

A single piece of concept art from Destiny was shown off a couple of months ago following a leak of some game details by way of early marketing material.