Sorry for the lateness of the reply; I've been smoking.
I recently went through a lengthy process of trying to find or re-create a sausage I recall from years ago in Texas - it was cured and smoked, fairly uncomplicated seasonings (not a lot of herbs or spices, mostly salt and pepper), but spicy with a good bit of mustard seed and, IIRC, cayenne. It could have been pure pork, pure beef, or a combination; it's been too long for me to remember. I only knew this taste from two places, a long-ago burnt-down beer joint whose owner bought the stuff from an elderly German farm couple in Tyler, and a meat market on a back road somewhere outside of Brenham, where they made a lot of venison sausage. To me, that taste was always vastly superior to the stuff from Elgin or most 'que joints.
I haven't found it commercially, but did come close enough by stuffing my own - straight ground pork butt, Bohemian Garlic sausage seasoning mix from Heinsohn's (New Ulm), a good bit of freshly-cracked Kampot peppercorns, a liberal dose of yellow mustard seeds, and a combination of cayenne and crushed red pepper flakes. Since I was smoking them on the low end of "hot smoking", I added Cure #1 to be safe. Smoked them around 160 over pecan, cranked the temperature up to 235 toward the end, stopped at internal temperature of just over 170, followed by a quick cold-water chill.