Ripole / Dipole experience?

anyone here have any experience with Ripole or Dipole designs with drivers from 15 - 18 inch? While this is not your typical pro application these kinds of cabinets work well in HT and home stereo where size is an issue and extreem out put is not too much of an issue. You can achiece 105 db of output with two t 12 inch units at a cost of about $70.00 Canadian per driver.  The real benefit of this concept is that it is as small as you can possibly make a sub and get deep bass. The design is not very efficient as you can imagine but it is tiny. This design produces a velocity transducer rather than a pressure transducer. Driver parameters are Fs 25-35 Hz., light cone, Qts of 0.6 and higher to achieve good bass. Here is a link for those who might be interested, http://www.audioelevation.de/frameSet.htm Most of the work I can find on these designs is being done in Germany and Holland. Regards Moray James.