Although, they are not 1:12, these were the favorite ones I found searching for modern lego dollhouses. After attempting to make something out of my toddler's Duplo's, I will leave lego houses to the experts.
These lego houses are creations of Michael Lasky. I'm really impressed how people can design these houses brick by brick. The few things I made with legos growing up looked like stick figures compared to these.
(images from mocpages.com/mocs.php?id=9683)