Try super-absorbent swim towels, something like this: http://www.swimoutlet.com/product_p/4226.htm

I've read (and believe) that most body odor is in surface sweat. In my old ~8 mile commute I'd use a swim towel to wipe down in the super roomy handicapped bathroom stall & change before work. (Three cheers for the Americans with Disabilities Act!) One really nice thing about swim towels is they're supposed to be kept damp and come with rigid plastic containers -- so you're not just drying off, but also cooling yourself a bit with the damp swim towel.

Plus the swim towels are compact, machine washable, and, since they're supposed to be kept damp, you can take 'em out of the washing machine and put 'em straight back in the plastic container.