I would recommend trying the Dynaudio SUB250's. I'm a huge fan! I posted this in another thread, but its relevant here too:
I am running this exact setup (MMG and 5 2200's) with a Outlaw 990 preamp, and it sounds amazing. I cant believe a speaker this inexpensive sounds this good. On a whim, I bought a set from a fellow at work, just to see what Magnepan was all about. I actually ended up replacing my Dynaudio contours in place of the MMG's - imagine that! The 2200 is an EXCELLENT amp, has never given me any trouble and has driven anything I've owned. They also drove my contours great (which are also known to be very inefficient like the Maggies, albeit less so). In this setup when I want to play it LOUD, I put it at around -10DB, so there is ample room to go even louder. I have run it at 0db and only then did they start to break up, but it so loud you'd never listen to them for any period of time.

The Magnepan MMG and 2200 monoblocks is a match made in heaven. I should note that I pair them with a pair of Dynaudio sub250 subs. I've actually placed the MMG's on top of the subs (they stick out just a hair, but still look good) so they are closer to ear level, and this made a huge improvement. I shoot the MMG's horizontal with a L bracket the previous owner gave me. The MMG's and Dynaudio subs sound really excellent together. The 250's blend well with many speakers because they are so accurate, but not jarringly so, and the MMG is no exception.