I believe North Creek used a 12"Peerless XLS and passive radiator. You can buy these from Madisound or Partsexpress. There are alot of other good drivers out there it appears, Partsexpress RS, TC Sounds, Aurasound. I built two subs last summer. One used the GR Research 12" and a passive. The other used the 15" Bully, now sold also by AcouPower. Both were very good in my opinion with the Bully having more output. Either would be a good choice for stereo. The AcouPower drivers certainly look interesting. Which ever driver you decide upon I think it is important to build a very rigid well damped heavy enclosure. I wonder if you could comment on the other subs you have built from other manufacturers?