I know its easier to buy or get someone else to make one, but it shouldn't be a big deal to make your own - you've got a lathe after all!!
Plenty of reasonable options for indexing to mark the divisions depending on what you've already got. Can be as simple as a strip of paper with the correct number of divisions wrapped around the chuck.
Alternatively a 3D printed dial, but then the majority of the work is in the design side, so probably not viable for a one off unless you're able to do it yourself and get someone to actually print it. Unless you can find a suitable dial to use on one of the 3D printing repositories like Thingiverse.
Steve