Don't know about that "big guns" stuff,but TakeitEZ pretty much covered it.
There are good holding cabinets that hold at about 140º,and introduce enough moisture,to hold large meats ,well,for a very few hours.
Now ,logically,if you have cooked a product to 120º-rare beef,long term 140º will eventually settle at the cooker temp.
Hope this helps a little.