To the chainline issue: "The most interesting part of Barre’s Cross Check singlespeed is its drivetrain. Barre mounted two chain rings to the alloy crankset, and the rear wheel’s flip hub had two cogs mounted to the fixed side, implying the Barre adjusts his gearing based on the ride."

Seems unnecessarily complicated to me-- it's effectively the slowest shifting 2-speed drivetrain possible. If you want more gears, get a 3-speed hub. Easy.