Acoustic Zen has many of the properties you seem to be looking for. I'd give them a call and see if you could set up a demo of either their Satori or Hologram cables(they're very customer oriented). Oodles of midrange, lots of detail, and plenty of extended bass. While you're at it you might want to demo their interconnects as well--I'd start with the newly reformulated Matrix Reference which also really fleshes out the midrange and should nicely complement your B&Ws(I use Silver Reference from source to pre and Matrix Reference from pre to amp along with shotgun bi-wire Satori cables). Best of luck.
Tim
Tim