I just read this thread last night, and, having never heard of Slawsa, I checked where it might be available in NJ. It turns out there is only one place: http://www.highlandmarket.com/
And, in an amazing coincidence, my wife and I had earlier decided to take a day trip today to the towns of New Hope and Lambertville, on the Delaware River. Driving there involved a short, but scenic, detour down Rt 519 to the one NJ source of Slawsa. It set me back $5.49 (it's a gourmet shop), which turns out to be just about the cost each if I ordered 6 of them from the Slawsa website, including shipping.
Interesting stuff, looks like that mustard based pickled condiment in jars everywhere, and yes, also looks quite a bit like Rutts Hut's famous relish, but it takes like neither. A little spicy, and worth a detour. It didn't knock my socks off like some of the reviews, but a nice change of pace. I may order a 6 pack.
So, thanks everyone for the tip.
Here's another on line article about the Slawsa people. http://www.timesfreepress.com/news/2012/apr/03/slawsa-family-recipe-launches-local-business/