I heard that an open bag of charcoal briquets (not the match light type) will suck up some pretty nasty smells. The Febreeze idea sounds good too. If you have a Lil' Chief smoker, you could cook up a pan of chips with the smoker in the car. Might not get rid of the smell, but it'll sure cover it up.

I remember back when my dad would turn on the shower, then sit on the pot and smoke a cigarette while he waited for the water to warm up. The bathroom had the nastiest smell ever invented-
sh!t, smoke, & steam all rolled up into one. Took a good hour before anyone could go in after him.