I love the idea of having a very elegant looking black and white powder room but don't know how to go about pulling black into the room. The room is a decent size for a powder room. The toilet and sink are white as well as the floor and I don't have the budget to redo them at this time. I feel like black on the walls or the trim would be too harsh but think that without black on the walls that room will look very stark. Any pictures or suggestions would be great! Thanks!
I'd consider painting the walls black in order to achieve what you've described. If you do a search for black rooms, black paint colors, I think you'll get many hits that will provide super inspiration.
Biggest concern with black walls is that the black eats the light and reflects nothing back into the space -- not a big deal since you're talking about a powder room. You may have to play with your lighting a bit because it does need to be adequate, but it's not like you need intense task lighting for a powder room.
Pittsburgh Paints has a couple good blacks for wall, get it mixed in their Accent Colors matte base. ICI's Dark Secret is one of my favortie blacks. Just don't have it mixed in any Glidden product from the Home Depot. Definitely need to find and ICI store for Dark Secret.