This new speaker by Cyrstal Cable is VERY interesting:
When Crystal Cable launched the original, glass cabinet Arabesque in 2009, the audio world was stunned by the performance of a speaker that sounded as clean
crystalcable.com
6moons.com
TL;DR: it has a passive-active crossover, meaning it uses a buffer stage that replaces plenty of crossover parts (yet the speakers still use a traditional passive crossover, just very reduced) for the entire frequency range. This reportedly gives a less reactive impedance and increased sensitivity. The specifications are 16 ohms/95db 0_0.
To clarify, it doesn't use an amp to power the bass, it has a current gain buffer to help the amplifier of your choice driving the speaker.
I'm impressed by this. Very, very smart solution. Shame it is so small tho, I wish they built an upscale version with a real woofer (10"+ inch)