Consider taking an older puppy, or even an adult dog from a shelter! An older animal wouldn't have to go out quite as often as a pup tends to.

I would steer away from the more active breeds, most young Border Collies, for example, would go nuts with that much alone time, but there are plenty of dogs that would be fine, given some adjustment time and establishing a routine! Dunno about Shiba Inus' activity level ... but we have Shiba owners around here, I'm sure they will chime in!