Jack Daniels.
I actually did do that for Abby once because NOTHING else worked. Just a teeeeeeeeeeeeeeny little bit on a qtip.
I also used to get a corner of a washcloth wet, and freeze it, and then she would chew on that, it seemed to help her a little bit.
Have you tried alternating tylenol and motrin every 4 hours? My dentist has recommended that for regular tooth pain, so I would assume it would work for teething, and the ped has had me do it with the kids for other things.