You did a wonderful job! I have never had the courage to ask for that much for a T-shirt quilt but in my area no one would pay that much anyway. I consider myself lucky to get $450 to $500 for a T-shirt quilt and that is inclusive of materials. Maybe I should rethink my pricing?? However, I do not do that level of piecing for sashing. Usually I do sashing strips and cornerstones.
Additionally you must be wicked fast to peice all the background squares (even strip pieced those would take me some time to do), cut out the shirts, back them with interfacing, quilt and bind this in only 45 1/2 hours? Maybe it is just that I am wicked slow.