The only person I know that specialises in Sports Bar Towels is Hatton Textiles in Exeter:-
Hatton Textiles: Designers and Manufacturers of Jacquard Woven Towels
Of course, he does personalised woven name towels, however, not sure whether he may have a stock of 'standard' ones. If he doesn't sure he will know where you can obtain them from. Ask for Jim Hopper.
You may find some by googling, of course, in the meantime.