Here is a "before" picture of a wooden doll house toilet, bath tub, and sink. I'm still experimenting, but these are solid and playable. I plan on painting them white. The toilet lid will hinge with a small bit of fabric glued on. You can buy various sized dowels in the craft section of stores, or from a hardware store. I made this picture a little larger than normal so you can see the pieces and how they're put together.
As a side note, the wallpaper is scrapbooking paper and the floor is too - it's covered with clear plastic laminate. It is from Joann Fabric and Craft Stores and looks really nice installed.
Here is an after picture of the bathroom... First I painted every thing white. The sink part I painted a little bit of an off white to make it stand out more. The toilet flush handle I just painted on with a bit of grey paint. Same with the bathroom sink faucet and handles (I couldn't find anything on hand tiny enough to look realistic, but will keep looking!). The bathtub faucet is a metal hook and the bath tub's hot / cold water handles are earring posts. The pictures on the walls are attached with Velcro so they can be switched around. The pictures are those small ones found on the backs of calendars. Then I glued them on foam paper. The mirror above the sink is a small 1 inch mirror from the craft section, and I glued it to the middle of a piece of foam paper, and then cut small pieces to form a border around it. The toilet I ended up making hinge with a small piece of white duct tape.