As I've mentioned before, I have an exotic Hardinge: a TL10. As you might expect, Hardinge taper attachments are pretty rare and pricey. The one that fits the TL10 well, I think I've seen one...
The reason this project exists at all is that Ken (shaylocomotives-at the domain of-charter.net) has castings for the way and the slide ($50) to match the Hardinge design (which is available on the Hardinge Lathe group). The base casting is much more complicated and runs $125.
True to form, I started with measurements and 3D models (since I wasn't totally sure where all the bits were really supposed to be). And, of course, I might have put a non-stock digital read out on the top edge of the mounting surface for the taper attachment
https://madmodder.net/Smileys/default/doh-45.gif It took a few tries to get the dimensions right, but it resulted in a functional taper. Not very precise, of course...