I used the cut off tri's from my Lucky Stars quilt top to make HSTs, then arranged them into this doll-sized quilt. It's about 20" by 25".
I also pieced together the back of my Shirt Stripes Boxes quilt last night, and I'll have to take a photo later, because it turned out very interesting! It took a total of 19 shirts to piece both the back and front, though many of them were children's and ladies' sized shirts. If I had been able to find more men's shirts, it would have taken fewer.