Place all ingredients in crockpot and cook on low for 7-10 hours. Once roast is falling apart, remove roast and shred in a large bowl. Skim out pepperoncinis and add to the shredded roast. Reserve the au jus liquid.
Split rolls in half and place on a cookie sheet in oven to toast 3-5 minutes, remove from oven. Place shredded roast and pepperoncini(about a cup) on one half of roll and ½ cup shredded cheese on other half. Put back in oven to melt cheese. Pour au jus liquid into individual cups for dipping. Serve.