Apparently Lara went ahead and posted something on Greenscene - whatever that is - because I had 2 emails from OC students this morning offering to design a product label! No idea what she said - do they expect to be paid? Do they have any talent or experience, or only enthusiasm? Whatever they have it's more than I, so happy to have their help.
Thought of a variation on Madeleine's flap strap idea, based on what Thibault said about creating an identity for the product, namely, instead of a strap that goes all the way across, have 2 straps on both sides that can be tied in the middle, sort of echoing the "wrap" theme (as in a present). It also mirrors the way the shoulder strap is tied.
Do not yet have a solution for the shoulder strap problem unless widening it is the answer. I throw this out to the great Wrap community!