My favourite place to find ideas is Imagineourlife.com Stephanie makes the best patterns to follow and they are free and mostly step by step instructions. I have just finished making her dolls house quiet book for Nate and he seems to be enjoying it, mainly by putting the bath duck in the oven. Using Stephanie's pattern I also made a little boy doll by just adding a little brown hair just so he had both.
Above are my versions of the kitchen and bedroom page. The backyard page was the last I made and I still haven't had the chance to photo it. You'll find the patterns here. Have a look around her blog because there are a lot of great ideas. The book I'm currently working on uses the same dimensions as Stephanies but is based on Nate's dads illustrations which you can see here.