I still enjoy my Oris/10Pi combo. A friend built an Oris replica and tried a Seven Pi loaded with an Altec 421 15" - he wasn't overjoyed with the result and has gone to a BD Design BD15 driver. Better, but he was still wanting deeper bass so is building a big bass reflex for the BD15.

Upshot of all that is maybe the seven Pi is the way to go - but I would use the JBL 2226. If you want to try different or vintage drivers, maybe the 10Pi is the better bet. Just my speculation based on my own and my friend's experiences.