Greg Zeschuk has told 360Zine that there is a slight chance Mass Effect may expand past the initial planned trilogy.
“We’ve said Mass Effect is supposed to be a trilogy,” said Zeshuck. “So you’re going to see at least a third Mass Effect, and even more if everything goes well.”
Zeschuk continued by saying that the company will “always be building more and more breadth” into its franchises.
More through the link.