Here’s one that was posted here at the end of March and seems to have been posted for quite some time so it may not be available even though the ad is still up.
I'd stick with KDS-18 through KDS-20. The 21-23 series have only one final rinse which is barley adequate.
These machines are 40-47 years old now so patience is the key to finding a lightly used one. They were all over the place 15+ years ago when they were being purged for something newer. Those newer units have probably been recycled by now.
I have a KDS 20 now and it has some rust issues on the bottom next to the filter screen but runs and cleans like magic. I am trying to figure out the best way to sand down the rust and reglaze. I also have a KDI 58 and hoping to pick up a KDS 15 this weekend. I missed a BRAND NEW KDS 20 two weeks ago.. I can’t seem find much out there.