Your problem is the "who the hell knows" part. If it wasn't for that you'd be o.k.
Don't see much for it but to drop the pan. You could, of course, just run the engine and see what else gets ground up which would give you an idea of where it ended up but personally I'd drop the pan.
Another option would be to cut a 6" dia. hole in the bottom of the pan to give you room to get your hand up in there to feel around for it and then just JB Weld the hole up. Looks a little ugly and it's hard to get it to stick with all the
oil dripping out of the hole but just keep trying it'll probably stick eventually. Shouldn't take more than a couple of weeks to get it right.
Hope this helps );-)
DonC