Chipper, have you looked in Costco where you are? Sometimes you can find "restaurant" stuff like the single serve items in those warehouse club stores, such as Sam's, etc.
Also, if you know someone (well enough) in the restaurant bus. that has an account with Monarch, Cysco or PYA you could ask them to order a case for you. It won't be cheap though.
Also, most of the deli/salad bars at the grocer have those single serve dressings available next to the take away food, so you could start picking up a few extra packets on your trips to the market.