I have a used Simrad/Navico WP4000 autopilot with wired remote that appears to work fine. It powers up, the controls work and the internal compass seems to work fine. I wasn't able to mount it on my sailboat due to location of Lazeratte covers.. As can be seen from the pictures there is some wear to the unit and it looks like there was a repair to the drive wheel but it seems to work fine... I held the drive wheel and there was not slipping and it felt powerful, which I know probably doesn't really mean much! I can't locate the u-bolts to mount the wheel but easy to find replacements. I'll keep looking. Belts are available in a couple of different sizes depending on application.
Shipping would probably be around $25 in Continental US