Well, I finally got around to making it into a throw blanket! I picked up some dark grey mottled cotton for the back, cotton batting, some double-fold black bias tape and got to work. It came out pretty well - honestly I kind of rushed through it, I'm not sure blanket-making is my thing. Plus, the Marimekko picks up lint like crazy, but it's warm!
Special thanks to Red Pepper Quilts for having lots of nice tutorials!