I wanted to update everyone on this.
We switched move to .com from .net. 301s were all in place. No other changes.
We've lost about 30% of search traffic. Within the last two weeks, traffic has leveled off -- it's been flat so I'm expecting that the worst is over. WMT is showing a boatload of our urls getting reindexed which makes me feel a bit better.
Here's to a rebound these next few weeks!