Pym created the (oops) villainous robot Ultron, which in turn created the Vision, a synthezoid whose emotional intelligence was based on the brain wave patterns of the once and occasionally dead Simon Williams (Wonder Man). The Avengers turned Vision against Ultron and Vision became a hero and member of the Avengers.

Bringing Coulson back from the dead would be dumb. But I could allow for Coulson's psyche profile to be used in programming the Vision (instead of Simon Williams) as it would make him more likely to be accepted by the rest of the group (from the viewpoint of his creator/creators).

The question then would be whether to introduce Ultron in Avengers 2 and Vision in Avengers 3, or skip the Ultron step all together and go straight to SHIELD designing Vision themselves in Avengers 2.