In addition to the Iron Man 3 animatics that got posted today, Federico D'Alessandro also posted 4 scenes he worked on for The Avengers, likely based on preliminary versions of the script (one scene is dated from early 2011).

The 1st is labeled as an alternate introduction for Iron Man and features Stark attacking a convey of gun runners before duking it out with a cyborg guerrilla:

The 2nd scene is an alternate take on Loki's first escape from SHIELD's desert facility. In this version, Iron Man arrives to chases Loki and evil Hawkeye through a subway tunnel.

Even more Iron Man in the 3rd scene which is an alternate version of Tony and Loki's confrontation at Stark tower, and plays out a bit longer than than 'role call' version we got. Here Loki uses his brain washing powers to lure Stark onto his side by appealing to his darker nature, before going into a 'survival of the fittest' sales pitch:

Finally, we get an alternate version of the first half of the final battle between the Avengers and Loki's army. The most interesting piece is probably the group shot at circa 17 seconds in which shows Wasp flying alongside the team. She doesn't appear anywhere outside of that shot.

You find these animatics on D'Alessandro's own website here, along with the ones for Iron Man 3 posted earlier today, plus more from Captain America and Thor.