While perusing the 'net looking for all things beef and gravy, I stumbled upon this article (even though it is not necessarily food-related) that talks in some detail about the hot beef commercial sandwich.
Apparently, the cafe at the infamous Wall Drug in Wall, South Dakota, serves a "hot beef commercial." This is intriguing, as it is somewhat of an anomaly. The article even states that outside of Minnesota, this is usually called a hot beef sandwich.
In statistic, they would probably call this an "outlier!" I just thought it was interesting that Wall Drug called the sandwich by this name.