I have a whole page on finding parts for your Skymaster in my "backup" website at
www.SkymasterUS.com and some of the vendors listed there may be of help. I would try Don Nieser at Commodore (405-503-4686 or 722-4079) or Preferred Airparts (800-433-0814) to see if they have a new surplus unit.
You can also try some of the salvage yards for an "as-removed" unit, but follow the advise on my web page when buying such units.
In the web page I also give guidelines on the type of things you should buy new (surplus-new, if possible), those that can be bought in overhauled condition and those that can be bought "as-removed" (essentially from a parted-out aircraft). If you can find this in the surplus market, this is the kind of unit I would buy new. It shouldn't be that expensive, it's costly to install (if a used unit fails after installation), and a used unit has probably been eaten away by the same environmental forces that caused yours to fail (so it may not last long).
On the matter of the board, please note that no one gets "accepted" to this message board. Kevin runs it for the benefit of Skymaster owners and pilots, and everyone can participate, as you do now. There is no Board of Directors or other governing body.
A different outfit, the Skymaster Owners and Pilots Association (SOAPA), which mostly organizes the annual meeting, does have a governing body. Jerry DeSantis, Paul Rooy and others are involved. Send them an e-mail if you'd like to be considered, but having participated in the organization of two of these meetings, it's a lot of work! BTW, Kevin is kind enough to cover the activities of SOAPA in this website.
Ernie