I would bet it would work for either one; knitting will stretch enough and they are pretty close in size. If it turned out too big for the smaller one, you could always add a bit of foam to pad it or something...
My daughter saw the pattern and immediatley thought "clutch purse." I think if you lined it and put in some plastic canvas or something like that between the layers to stiffen it, it would work. I think I'm going to try it.

I'm looking forward to it - we have some blue and a variegated blue/purple/brown/green left over from his hat-scarf-mittens combo and I think it's be cute to have a matching case for his ds.