I've seen a few videos of Blauer's SPEAR system at CrossFit.com and found them fairly interesting. He's not trying to teach some self defense style: his entire program is based upon the "flinch" response, what the human body naturally does when it feels itself threatened.
His work basically involved studying where most knife or gunshot wounds were located, and there was a statistically significant number of these wounds located on the hands and arms. He also studied photos of people who were surprised: most people's reactions are to "flinch" : bring up the hands and arms to protect the head and torso. His SPEAR methodology is basically a first response defensive posture where you use the flinch to project out your hands and forearms into a triangle to both block and attack any incoming threat.
Here's a video on youtube, originally from CrossFit:
He calls it a bridge to the more complex gross motor skills (i.e. techniques) of your martial arts style of choice; its for self defense when surprised, not for sparring or any other "competition."
Here Blauer discusses the bridge concept:
Guess what that looks like? A lot of the preemptive atemi that many adept aikidoka already use. Combine this with moving off the line of attack? Well, I guess thats what I'm going to be spending the rest of my life to try to train into my natural movements.
Also, just for fun:
That last one was added to CrossFit on April 4. :-)