Other then in publications, I have not seen the camera. Polaroid also (apart from Wisner's efforts) has three of the 20X24 cameras (not Wisner) out. I believe that they are rental or leased units.
From what I understand about Ron Wisner's business model I don't know that I would go in that direction.
Additionally, there is another fellow that has hand built and is using a 24X30 camera and it uses Polaroid materials as well.