Of course you realize that Grey Poupon, America's favorite Dijon mustard, is made by Kraft Foods in New Jersey.
Trader Joe's Dijon, by contrast, is made in - of all places - Dijon, France. So is their Grainy Dijon.
Another fascinating site - and attraction - is the National Mustard Museum in Middleton WI. You should ask them if they have the Amora mustard inquired about upthread. If you're ever anywhere near Middleton, I strongly advise you to visit. It's a complete hoot, as well as offering hundreds of varieties of prepared mustards from all over the world and many gourmet foods, condiments, and sauces. Admission is... free.
You can even procure a handsome, suitable-for-framing diploma from the Curator's Alma Mater, Poupon U.
EDIT- Just made that search: they got it! A paltry $6.75 for 15.5 oz.