Yeah your best bet is to do some hunting through seeds. Either a nice NL5 cross, or one of the various NL5 reproductions. Grow a ton, find and keep the one.
Also mind you, most people's recollection of old school NL or NL5 is probably from Neville's seed stock, unless you were in the know in the pacific northwest US. That's kind of important because it means Neville's selections were really friggin good. He came from a large scale agriculture background I think, so he knew his stuff. That said, I'm not aware of any other NL seed releases of old that anyone speaks of... so as much as we talk about Seattle Greg and whoever else was involved, the truth is Nevil really brought it to the masses, and Nevil's secret sauce was the true magic of the NL lines. The proof is in the goods. I don't know what plants these other people had back in the day, but I do know who brought the goods...
Probably the only other NL seed release that's highly regarded was BSCB's repro of Nevils NL5