I took a serger class years ago, & the lady showed us how to make a t-shirt/sweat shirt. It is in how you fold your material & cut. (all rotary cut) If any one is interested I would be glad to share the pattern/cutting directions w/ you.
I have made jackets-long sleeve as well as short sleeve t-shirts with it. The jackets are all zip up the front & I even got adventurous and put hoods on them. I have made my jackets out of fleece as well as cordaroy(sp). Also light weight cottons.
I have not made them out of quilt sqs, but don't see why it wouldn't work. There is NO stay stitching involved & it all goes together like a dream. Also, there are no "set in" sleeves.
Thanks for your time.
Billie