As of October 2015, there are no free dollhouse blueprints online, but Finescrollsaw.com has dollhouse design sheets that are free to download. These designs, from the late 19th to 20th centuries, have been restored with the latest graphic technology.
At Finescrollsaw.com, the dollhouse design sheets are listed as "Hobbies Special design 186 Doll's house" and "Hobbies Special design sheet 133 Doll's house." To view the designs, click on their links that open a PDF file, showing templates for each piece of the house. At the bottom of the designs' page, there is a color photo of the "Hobbies Special design 186 Doll's house."