One of the staff on the development team recently stated on the "Dragon Age Discovery and Learning" thread on Bioware Social Network that Dragon Age will not end at a trilogy.
When one of the posters asked for confirmation, executive producer Mike Darrah confirmed that there will be multiple Dragon Age games in the future.
Several other queries were addressed by the development team, such as the amount of cutscene dialogues in Dragon Age III (according to Mike Laidlaw: not much).
The thread is currently closed. There will be a new question for the month of June.