I have a teenager. I can live with one bathroom for a little while, but it would be a tough thing to think about long term. There is a really large second closet that used to be a sleeper porch off of my bedroom and the inspector said it would be a fine bathroom with a little floor bracing under the tub. I've since decided I'd keep everything as close to an "original feel" as possible. Sure, I know there would not have been a bathroom on a sleeper porch, but, I can't think of a better place to put it. It will raise the value of the house immediately, too.