How about sparsely echo quilting? I'm thinking of lines to echo the strips, but only 1 in the smaller areas, and just a few in the larger, random widths apart, just as the strips are random. They could stay in their own block, or spill over into adjacent ones, depending on where a line of stitching could keep traveling in a kind of meander-but-with-angles instead of curves. I don't know how difficult that would be to do on a longarm--I'm imagining the finished look, not the process!