I have resurrected another old file from my Shapeways days. These were very expensive on Shapeways for an esoteric item since I had to sprue four of them together and the size of the respective file.
I think they sold for something like $27.00 on Shapeways and despite the cost it was a modestly popular item.
I now offer them as a 3D printable file on my Cults3D store.