This pattern is from Tanya Whelan (http://grandrevivaldesign.typepad.com/photos/grand_revival_patterns/index.html) at Grand Revival Design. It was super easy to make. The pattern came with two different sizes for the bags. This is the larger version.
Unfortunately I let my daughter play with this bag a bit, and I didn’t construct it very well, and the seam at the top of the strap came undone. So sad.