Have you considered using something like this ? You might have to be careful about how hot they heat up though. I'm sure you could wrap them in a cloth to insulate them.
I bought a small humidifier and stuck it to the dashboard of my car. It's powered through the cigarette lighter and it's invaluable on long journeys. I bought it off Amazon. They have more types of mini ones available now than when I bought mine so you might find a better version. I've put all parts (except the motor) through the dishwasher a few times now so it's easy to clean too.
On a side note, how do you cope in Vegas? I always imagined it would be the worst holiday to take with dry eye, with all the dry heat outside and the air conditioning inside!
The eye altering, alters all - William Blake