Update: I had some rye whiskey on the rocks, which helped me think very clearly and remember the powers of magnetism. I used a big frickin' 1" neodymium magnet disk to slide the stud up along the passenger side of the oil pan, near the intersection with the block. Got it about half way along there heading towards the subframe and the magnet lost it.
Is it safe there? Maybe I can find it and continue working it towards the drain plug...