Hi Mark:
I am familiar with pypilot, and with modifications it might be a good choice for a Harryproa. It doesn't have the bells & whistles of the latest commercial autopilots, but I'm thinking a Harryproa will be pretty directionally stable and not need much in the way of autopilot smarts.
I did have some fun at the Miami boat show talking to the guys in the electronics booths (Raytheon / Simrad / B&G / Garmin etc.) There eyes crossed and they became incoherent when I started asking how their gear would work on a proa. So I don't think there's going to be much help on the commercial front. :-)
I have the preliminary C50 drawings from Rob & Steinar, but the rudders & linkages are conspicuously absent. It'd be nice to get all of the autopilot gear belowdecks with no possibility of seawater intrusion; we'll see if that's going to be feasible.