I'm with Sal, above, on the Jensen M-18. You can actually buy new replicas of that monster at G.I.P. Laboratories. I know of a system that is being designed to use 4 of those drivers, plus G.I.P. 555 midrange drivers, plus the G.I.P. version of the 597 tweeter. A custom Tungar power supply with hand-wound transformers will power all three field-coil drivers. I don't know about the crossover. The midrange horn is a modern-build 15A replica. Just the drivers and horn are well past $100k in cost.
On just a price basis, the likes of Accuton sell bargain drivers compared to companies like G.I.P., ALE, Cogent, Goto and Feastrix.