I've made my biggest dollhouse this far by using three book shelves adding to it cardboard and wallpaper. Most of the furniture I have made of cardboard from food packages by covering them with self-adhesive vinyl and adding card pins as the pulls.
The house is 2,8 meters long and about 2 meters high.
My dollhouse house is now to be seen in our local art center Haihatus until the end of August. Here a short video of the house and its' yard in YouTube.