I didn't make a new pattern, but the diagram below shows (in red) how to change the howl into a cape.
For my version, I used 1/2 yd of fleece and made the cape as long as possible, using the selvages as the bottom edge. Since it's fleece, you don't have to worry about edges fraying, and thus no lining!
I sewed the back seam WRONG sides together. Then I pinked that seam (optional, I just wanted more zig-zaggi-ness). I cut some triangles from a sheet of (fake) wool. Sandwich them in the seam, then top-stitch the seam closed (I used a zig zag stitch). I used a piece of the fleece and velcro to create the closure.
This is very boy-ish, but I could see this being a cheap and easy Little Red Riding Hood idea. Or just make them without the extra embellishments. They are quick and cheap and WARM. Perfect to add a bit of whimsy to a winter outfit.