I nominate Tannoy System 10 DMT, System 10 DMT II, or System 1000. Only the last of these is a current model, though they're all close to identical. Sold only in pro audio shops (they're professional studio monitors). Dual concentric drivers, around 93 dB sensitivity with high power handling, 42 Hz-25 kHz freq. response; approximately the dimensions you indicated; unforgivingly neutral sound; exceptional dynamics. I use the System 12 DMT (2 x 1 x 1 ft., so too big for your purposes), and am saving up for the System 15 DMT II, but unlike many smaller speakers, the 10-in. are of equal quality to the 12" and 15". Good with solid state or tubes.
