8 hours prior to serving, place 4 lb. rump roast into crock pot(if using a smaller roast, adjust cooking time). Do not brown meat prior to putting in crock pot. Pour over meat one can of beef broth, one can of french onion soup, and one bottle of beer. Cover and let if cook on low!
Check meat at 7 hours (sometimes different crock pots run a little hotter than others). When meat is very tender, take meat out of crock pot and let it rest on carving board and place aluminum foil over it to keep warm for 15 minutes. Keep juice in crock pot on low.
While meat is resting, split open philly sandwich loaves and brown in a hot oven for a few minutes until golden brown. Remove and put swiss cheese slices on one side of each loaf and return to oven until cheese has begun to melt. Also, saute' onions in a small fry pan if desired.
After the meat has rested, slice meat into serving portions and place into each sandwich loaf. Then, into individual serving bowls, ladel juice from crock pot and serve with each french dip sandwich.