ISO genuine Italian Beef at home

When I was in Chicago a year ago with Dave (who is from Chicago) one of my discoveries was how much I loved Italian beef sandwiches. Portilo's (I think that's the spelling) was one of my favorites. Since then, I've been trying to find a recipe that will at least approximate the gravy -- which I would call jus -- on those sandwiches, since I've accepted that I won't find a bread that is the same. I think I've finally got one, from a posting I made on the Cooking.com forums. I hang out in the forum quite a bit these days, and am having some fun with that. But back to the task at hand... As I said I think I have a recipe, at this point it's not done because the big ol' roast has to cool so I can slice it down, and marinate it in the jus. But it smells right, so I have high hopes.