You wouldn't normally find these in Canada, but we have Beef Dips (I think the Yanks call them French Dips) instead, which are the same idea, except served on a sub style/hoagie roll bun.
Cheese and onions are optional, as is horseradish. You get "Au Jus" with it, which is a thin gravy broth for dipping.
The quality of the beef is the most important thing, which is why it's sometimes hard to find an excellent beef dip.