Aaron pretty much covered all of your direct questions, but I'll add that the concept of CMP is an important one when talking about performance, so doing anything to disable CMP is something we very much encourage people to avoid.
Global variables just aren't necessary 99% of the time, as there are other, more efficient ways to do most things you would do in a global variable anyway. If you have some specific cases in which you're currently using globals, we can almost certainly help in getting those converted to a more CMP friendly format.
As Aaron pointed out a couple times, CMP is not just across blades, it's across cores, which means it's not just a Viprion concept, it's a concept that's used on most of our multi-core platforms. So yes, even with only one blade it's something that's good to keep in mind.
Colin