Just a few minor modifications to the original envelope clutch body and this is looking better already!
I'm going to try making it bigger now. This one is 7.5" wide x 5" high.
Since the flap is tapered and only has one snap holding it in place, I'm not sure how wide I can go and still have the flap lay down fairly flat. The corners will definitely start to want to curl up at some point, so I'll have to see what happens.