Are there no suitable absolute position encoders of the required parameters?

They cost more than increamental encoders.
the real problem with absolute encoders is that they can only be geared 1:1 to your machine.

so, if you get a 1024 step (I recall this being the highest available) absolute encoder, that IS your resolution. If you use an incremental encoder, you can gear it ti rothate many times for each revolution of your machine. On the rotary knitting machine I made, I could not have done it with a resolution of 1/1024 revolution.

Erik