Have you tried Walmart, Target, and your local sporting goods stores?
My opinion is it's going to be hard to find sweatshirts that don't have that dropped shoulder. I personally think they're rather sloppy looking and prefer the raglan sleeve style, but whatevs. Manufacturers don't care to consult me, lol.
Since I've not made any kind of sweatshirt jacket or sweater, I'm not going to be much help in the alteration department. Hopefully someone else will be able to guide you.