I'd really like an unopened bottle - tho thank you for the Steak and Shake reference.
I've looked in my local Jewel and Dominik's - nothing there - and also in a Wild Oats (?). If I get desperate, I guess I can make my own ... but there's something to be said for buying a condiment that exists purely because there are other people out in the world who use it, too. Plus, I really like that shaker bottle.
If anybody would know where to look, I figured lth people would. Maybe someone else will appear who will know for sure where to go.