You wrote :

"1. Buy fostex or lowther drivers and get cabinets built...designs exist all over the place, INCLUDING THE Manufacturer websites. www.quarterwave.com is also a good place to look at (though MArtin does use BSC networks so it may not be PURE single driver)."

Hmmmmmmmmmmmmm .... I guess I would contend that the speakers are pure single driver but used in a politically incorrect and not so popular full range driver system set-up. After all the driver does not know what is supplying, or modifying, the input signal so it just happily plays the music. In reality, any box is an acoustic filter already so all I did was add an electrical filter and a solid state amp.

Martin