Years ago I read an article about window quilts in Countryside Magazine. Luckily, I found this link online:
http://www.countrysidemag.com/86-6/sue_robishaw/
The article gives a detailed description of the framework, which keeps the quilt close to the window frame. Much useful information in this article. If you have quilts you no longer use for your beds (like ones you made as a beginner), this would give new life to them.