My sister made this spectacular headboard a month or two ago and I thought I'd share it. She started with a piece of MDF, foam, batting, and baseboard molding. I love that it isn't your run of the mill DIY headboard. The molding definitely gives it more personality and makes it stand out. For the molding she actually just used 3 pieces since you can't see the bottom.
I am on the hunt for fabric to match our bedroom so I can make one too. She also gave me the idea to use finishing blocks on the corners since we don't have a saw to cut the 45 angles. Hopefully I will get around to it this summer. I am looking to find a fabric similar to the kind on Carrie and Big's headboard from Sex and the City 2.