Finally getting around to install a stereo. Just parsed out all the wiring stuff and thought I'd add a note here on the Isuzu harness (IU02B).
Everything is a fit except that you have to connect the "Front" speaker wires from that harness to the stereo's "Rear" speaker wires. It's not an issue with the Isuzu harness but of Kioti's pin arrangement: from Kioti's schematics (mudplugger, once again, many thanks for the electronic copy of the service manual!) they put the rear wires in the connector where (by apparent standards) the fronts should go. If you were to wire the connector harness to the stereo according to the markings on the connector's and the stereo's wires things would work, but the stereo would only produce sound with the fader set to "Front," which would be kind of confusing (when there's only speakers in the rear of the cab), though it would still work.
I'm going to wrap this up and call it a success, though I haven't wired it up yet: I did test the wires with the connector harness plugged into the tractor harness and everything checked out.
Now I need to figure out how to physically mount the stereo! (and I thought the wiring was going to be the tricky part!) Going to start a separate thread.