i too will be starting with a dog next year. one thing i know is that if you have a pet, you can't apply to Albert Einstein COM because they require you to live in their housing and don't allow pets.
as for the walking. if you get a decent sized dog, 8 hours is no big deal. mine is only 40 pounds and she held it for 10 hours once. also, you may find pet-walking services in certain cities, or be friendly with your neighbors. or maybe find a teenager in the area who'll come walk your dog for a case of beer per week... uh, make that a case of
root beer.
worst case scenario, you paper-train the dog. that is, teach it to pee on newspaper that you'll place on a hard surface, ie in a bathroom.