Hutzal,
Your first suggestion already exists--it's the M60, except it has two 6.5-inch woofers. The 5.25-inch driver is a woofer/midrange unit, covering upper bass from 200 Hz up to a good chunk of the midrange. At 2 kHz, the 5.25 crosses over to the tweeter.
Using dual 6.5-inch woofers below 200 Hz enables more powerful bass output, and deeper bass as well as better power handling. The two woofers are roughly equivalent to a single 12-inch woofer in an enclosure of similar volume, but using two smaller enable much better control ("tighter") than would be the case using a large-diameter woofer. You can also make the enclosure narrower and less overwhelming.
