I can't tell you how well they would sell, but I can attest to how much time it takes to find the right sized cone and get it cut down and stabilized. My brother developed a keen interest in making a pine cone pen and it has been a time consuming adventure. Many cones look as if they're big enough, only to find that the center is not dense enough to allow for drilling without destroying the blank. He was successful in making one pen so far, and the results are incredible. His pine cone blanks look quite a bit different from yours, so I guess there's a difference between species.
With all the problems involved, I now know that $10 would be a fair price, and perhaps a good price, but whether people would pay that, I just don't know.