You might want to build a pair of those tower two π Speakers sometime. They're not transmission lines, but they are physically large cabinets and are tuned like you've described.As far as transmissions lines are concerned, they're essentially tuned cabinets like bass-reflex except they use 1/4 wave pipe resonance instead of Helmholtz resonance. The trick is to get the bass subsystem to take advantage of the waveguide's lowest standing wave node and maybe some of the lower harmonics, but to suppress all the upper harmonics.
Transmission Lines, Pipes and Ducts