Most knitting machine manufacturers that targeted the prosumer market have gone out of business (or left the business of making knitting machines). However, there are large communities of owners who still keep the flame burning.

One of the most interesting hacks I've seen is from a German hackerspace, who have taken two Passap E6000 machines and merged them into a fully computer-controlled "Frankenpassap" (only one bed on a normal machine is dynamically controlled).

https://www.hackerspace-bamberg.de/Passap_pfaff_e6000

I have a Passap E6000 at home and will soon start working on reverse engineering the firmware in the computer that comes with the device so that we can start the process of migrating to a more modern toolchain.