I found an evaporative cooling towel... like a chamois... at Harbor Freight Tools of all places! It's called "Chill Out" and is 33" x 13" in size. It's a pretty light blue color.

It comes in a plastic storage container to keep it moist between uses. It is also machine washable. I think the price was around $10.

I haven't used it yet, but I'm glad to see someone else having good luck with a simiilar product.