I saw the recent topic about a Snow Bros. proto, and it looked really similar to a couple of carts I've had for a long time. Granted, it might not be anything special, but it's at least worth asking.
First, pics of my own Snow Bros. cart. Pretty similar to the other one, aside from the shipping info still attached to mine. Forgive the massive images, by the way; I'm on a spare PC right now, and don't have Gimp here to scale them.
Front: http://img690.imageshack.us/img690/8...wbrosfront.jpg
Back: http://img163.imageshack.us/img163/3...owbrosback.jpg
And another game, Tale Spin, that looks close as well.
Front: http://img197.imageshack.us/img197/4...espinfront.jpg
Back: http://img688.imageshack.us/img688/9...lespinback.jpg