It sounds like a great solution. A place all to yourself.... but I encourage you to throughly research. I agree with all the earlier comments about consistent temp and insulation. Don't let that discourage you. It just may work....and could be totally adorable, comfy place for you.
I recall another board member that has done this very same thing. There are pics of her building and the wip. I will try to find the link.
*** Here is the link:
http://www.quiltingboard.com/t-103882-1.htm
You may reach out to her and glean from her wisdom!!
Good luck!