I've been passed this review for the Positron V114 Asterisk PBX blade which is the first one I've come across to date. A bladed Asterisk server  running completely independant of the underlying operating system is a fantastic concept we believe and savings on power consumption alone would make a compelling business case.

The article is available here

http://www.ipchitchat.co.uk/images/positron/IT_Jan_Labs_Review.pdf

The V114 is on sale here:

http://www.ipchitchat.co.uk/index.php/Positron-Asterisk-PBX-Blades