The barista at my local coffee shop and I have a running theory that Phil Coulson is one of the kids running playing Captain America at the end of Cap's flick, right before it jumps to modern times.
Another theory is that, maybe, Coulson is really an LMD (Life Model Decoy). Are there more than one of him? One to swing by Stark and Pepper's tower in NYC, another one to pick up Captain America?
And the third theory is that, like the cards, Fury lied to get the team together, and Coulson lived. This theory comes from the fact that the actor is supposedly signed for IRON MAN 3...