Indeed, this was a fantastic film, I'm glad the DVD finally came out because It was almost a 2 hour drive to find a theater that actually showed this ... and I wanted to see it again after watching it this summer
That said .... I doubt Rockwell will win any "big" awards, usually the awards for best actor always go to a big blockbuster, not some limited release 5 million dollar indie film.
I personally think the movie should also get the award for best special effects. Yes, District 9 was "cool" and had more action, but the usage of miniatures for moon, and the amazing level of achievement when you take into context the amount they paid to do it, was off the scale.
Duncan Jones did a great job with this too.