I think the key to the multi channel issue is that folks who are interested in just two channel stereo can live with the monoblock idea. In fact, many prefer to have monoblocks.
But once you start getting into 3, 4, 5, 6, 7 channels of amplification for surround sound, all those power cords and cases get cumbersome. Designing a new case that will allow the modules to share one power cord would afford SOME savings to the average customer (i.e. the one who isn't going to spend $1000 on a power cord for each amp), and a lot of money for those folks who do swap power cords.
Putting the amp into one chassis won't dramatically alter the MSRP price lower, but should afford some folks the opportunity to save a few dollars over the price of the monoblocks... I'm not so sure I would alter the power specs though.... 100 watts is pretty standard out there in receiver land (not that those receivers can actually put out their rated specs all channels driven)...
If you are going to do a 5 or 7 channel amp, it needs to be in the same chassis with one power cord for the average consumer....