Good news: the Saturn dealership down the street took care of business, replacing the intermediate shaft assembly. And they did it in less than a day! I was expecting a call most of the day that would start, "Sorry, but..." Instead I got a voicemail that said: "Your car's ready, we're open until 9. Have a nice day." Yes!
Fortunately we got the extended warranty when we got the car over a year ago so we didn't have to drop a dime. This is a smart thing to get if you're buying used, IMO. (Well, if you're buying used and you don't know jack about cars.) I got an interesting explanation from my coworker about front-wheel drive transmissions today, but if you asked me to repeat it I'd be able to barf up at most 10 percent of it. I have very little mechanical aptitude, which is weird because my dad could have inspired MacGyver.