How much to charge for a commissioned quilt

So how many times has this question come up? :-)

As I mentioned, I have been asked to collaborate on a shirt quilt for a widow, using her husband's shirts. She wants six lap quilts by next Christmas. Given the number of shirts and other woven apparel she has, I'm thinking about doing (or recommending someone else do) six 48" x 48" lap quilts, using the shirt fabric for patchwork, then buying fabric for a wide border on all four sides.

For at least one of the girls, I'm thinking of doing simple 4" square patched of the light-colored fabrics (e.g., dress shirts and seersucker), something like this:

For the boys, I'm thinking of using the plaids and dark fabrics, perhaps with a variety of more complex, traditional patchwork designs, something like this but simpler: I would expect to charge more for the latter type of quilt-top if I were just making one quilt, but it would probably be nicer to just spread the costs evenly over the several quilts, so one grandchild's quilt cannot be said to cost more or be more valuable as a gift and heirloom.

I am thinking of making the quilt tops, having them layered and long-arm quilted by a local shop (S.E.A. in Gulf Shores for the several of you who leave near here), commissioning embroidered labels (of the deceased husband's name and my own label), and binding it myself.

So how do I price my work for the quilt top and binding? I will be research this myself, of course, but it's usually more useful

And for you folks who live near here, would any of you be interested in making these quilts on commission if I don't have the courage? :-)

ep