Check out this hoodie-backpack! This particular one is pre-made and can be purchased for $25 to 35, but I bet a DIY version is super easy! It might require you to remove the kangaroo pocket and reattach it closer to the neck, but I think it would be worth the effort. I am definitely going to check for a large hoodie the next time I’m in a thrift shop. (None in my closet as I am partial to zip up hoodies as I can never seem to say one temperature.)
Above pictured bag also available in; Chicago Bears, Dallas Cowboys, Philladelphia Phillies,New York Rangers, Minnesota Vikings, just to name a few. You can also get the hoodie styled purse and tote bag.