For me, I have always done labels by using heat'n'bond (or steam-a-seam) on the back of my "label" fabric - generally something neutral that blends with the quilt.
You can write on it with the Pigma Micron pens or the sharpies or other permanent fabric pens. Most likely, I'll just send something like that for you all to sign. I've seen Joanns and most LQS carry the pens for $2-4 each (depending on the store & tax).
Another option is to print one out on an ink-jet (either using the premade sheets @ Joanns, etc or by making your own) and sending that out along with your row. The nice aspect of that is you can print it out - so you can get pictures or graphics or whatever in the world that you want on it.
Google "quilt label ideas" and then look at the images that come up. If you can't figure out how to implement your idea, throw it out on the thread here and we can brainstorm a way to make it work.