There was more leftover than I thought! Turns out that a lot of the pieces remaining were a similar width, having originally been purchased as fat quarters.
So I arranged them randomly and pieced them together in one long strip, the length of the quilt-to-be.
I still had a pile of 2.5" squares leftover from the quilt top as well, so I pieced them together randomly into two long strips. They've been added to the striped piece, separated by all the leftover green fabric from the quilt top.
And this is where it stalls. I have a little bit more in odd sizes of a couple of fabrics, so I might make another stripe or two, but I'll need to purchase more fabric yet. What would you do? More green? Batik or solid or something else? While it is the quilt back, I still want it to look nice.