I know there's an early proto populated playfield that was for sale in the Boston area. Not sure if he posts on Pinside or not, but he does on RGP. If you haven't already, take a look there (I think his handle is Pinflipper). Many people from the BPA buy from him, so he's a good guy to deal with. I almost picked this up the beginning of the year for my SWEP1 (has Nucore), but I found a regular instead.