Apparently an ex employee leaked the plot for the DLC (which he says has been planned for months) and even a new series of games set in the same universe as Mass Effect,
continuing the story where Shepard has actually become the catalyst. From what I've read so far, it would be really really really lame if they went down that path.
Check it out:
http://i.imgur.com/bcSRH.jpg (Heavy possible unconfirmed spoilers)