From what I can see, the N20 is a great boat and could continue to be great class. If indeed, Performance does not plan on promoting the class any longer, I would think it is time to grab the bull by the horns.
You do NOT need a factory to make a class.
Even the Shark Catamaran Class is still thriving.., and that is with one lone builder left. At one point they had NO builders (most folks just bought old boats and rebuilt them)

As I mentioned in another post, I can set up a class Forum for the N20 where you can conduct class business. It can be open (where anyone can drop in and see what is going on) or closed (where only members can participate).., your call.
And, you can optionally set it up to send emails to members on each post.
You can also run polls on a regular basis, elect officers, or whatever.
I can set up a moderator(s) of the Forum so you can administrate it.

I would then think you could follow the pattern of a solid, growing, self-relying class and get a constitution, lay out sail criteria, and whatever else that would make the class grow.
You could have a panel of members that could do nothing but promote the class. Set up a National Series Championship, a Nationals, a North Americans, and do whatever the hell you wanted to do.

Even though I am not an owner, I am fond of the design and would love to see this class hang around forever.
Rick