If there are separate drivers with separate terminations then the 20.7 can be bi or tri amped. Of course we are talking modding the thing. Stock it may have just one set of speaker posts and an internal series xover. This does not mean you cannot take the speaker apart and wire it any way you want. You could use a seriously tweaked analog or digital xover and get as crazy as you like. The first thing you would want to do is build some serious damped and braced frames/baffles for them. The magnepan stock frames are not very serious.
Magnepan announces the 20.7
Jacob Heilbrunn has a first look on The Absolute Sound's site.
"But here’s the skinny: no other speaker at this price will offer even remotely similar lifelike performance, and it should—no, will—scare the bejeezus out of most of its competitors. It’s no accident that Audio Research, which I also got to visit, has 3.7 loudspeakers as part of its reference system. So go ahead. Search for another loudspeaker. But I can only wish you good luck. I defy you to find one at up to five times the cost with the scale and realism of the 20.7."
http://www.avguide.com/blog/first-listen-magnepan-s-new-flagship-207-loudspeaker
"But here’s the skinny: no other speaker at this price will offer even remotely similar lifelike performance, and it should—no, will—scare the bejeezus out of most of its competitors. It’s no accident that Audio Research, which I also got to visit, has 3.7 loudspeakers as part of its reference system. So go ahead. Search for another loudspeaker. But I can only wish you good luck. I defy you to find one at up to five times the cost with the scale and realism of the 20.7."
http://www.avguide.com/blog/first-listen-magnepan-s-new-flagship-207-loudspeaker