You should be able to tweak most any onion dip and add bacon.
I like the one in the 94 (?) edition of Joy of Cooking.
Off the top of my head, it's something like this, and I know I'm forgetting something so we should be safe from copyright infringement.
2 cups finely chopped onions
1/2 teaspoon dried thyme
2 cups beef stock
16 oz sour cream
1-2 tablespoons balsamic vinegar
1 shake of hot sauce
In this recipe, you simmer the onions and thyme in the stock until the liquid is almost gone. Add the hot sauce and stir through. Add that to the sour cream and balsamic vinegar. Stir to mix and chill for a couple of hours.
To do a bacon version, I think I'd chop and saute the bacon, cook it crisp. I'd want about 1/2-3/4 cups when I finished so I guesstimate that at about 1/2 pound of raw bacon.
Drain the grease, proceed as above using the bacon pan for cooking the onions in order to pick up the brown cracklings from the pan. Leave the bacon in during the simmer time too. I wouldn't add the balsamic at first. Chill it without the balsamic. Give it a taste, and add some balsamic in small additions if needed. S&P to taste. Shouldn't need much salt as the stock and bacon will add a fair bit.
I suppose it would need some garlic too.