I've been an MVP Gold for 3+ years now and can say that notwithstanding what the rules say... you can get lots of upgrades outside the literal wording of the rules. My experience is that once the paid MVPG upgrades are taken care of, there is lots of discretion by the gate agents (and even the agents up front before security checking you in). I always ask at the front and then again at the gate, I make it clear I dont expect anything. I'm almost always treated with a friendly smile and a "we'll see what we can do.."
I have (or my wife) receieved upgrades in the following circumstances:

• me flying alone on a coach award ticket or AS50
• my wife flying with me as a companion on a coach award ticket (me on a paid coach fare)
• both wife and me flying on coach award tickets or AS50

This is one of the reasons I've stuck with AS. NW incidentally does the same thing although it never seems to work out quite as often on NW.