No luck at the junkyard. I did a little better online. I found a guy in Clarksville, TN selling half a dozen Autolite and Motorcraft carbs. He's asking a little more than the junkyard wants (he's asking $50, they're usually about $30 from the Pull-a-Part) and I'm meeting him tomorrow.
I emailed one guy with a Holley four-barrel ($35) and another guy with a Holley intake for a Ford small block/Windsor ($80).