I know of several DIY speakers with detailed info which uses nice drivers. But I have yet to find really high end ones like B&W Nautilus, Eggleston's or Dynaudio's. Only in the "horns side" I have found the Oris, which seems really nice and some say can compete with Avantgarde's. Some requisites I can think (please add more if you know them) is a really stiff cabinet carefully designed (in volume) around the drivers. Different chambers for every driver, an impeccable designed crossover and, of course, the best drivers one can find (Scan Speak, Eton, etc).