Good luck. Seriously. I'm 6'4" but like a large frame, and my brother is 6'7", so I look for 65-68cm frames everywhere I go. Not counting the Rambouillet and Atlantis I bought from Rivendell, I've found ONE in 20 years. It was a mediocre steel (stamped dropouts, no-name tubing) one that measured 27 inches center to center. I bought it for $20 and rode it for a year or so, but it was too flexy for my 240 pounds.
Seems like you could find at least 65s until maybe 20 years ago, then they disappeared. When I ask in bike shops now, they usually try to steer me to a 62, which is the largest most shops stock.
Kind of a long shot, but even though you don't want a vintage frame, you might check thrift shops for a few weeks. Most of what you'll find is junk, but I've scored some real bargains there. My singlespeed is built from a Reynolds 531 Trek touring bike I bought (with Brooks B-17) for 40 bucks.