Yes, of the blower systems I had posted I have actually tried the first and third I listed (copy below). As you had mentioned that the design you favored required that you purchase a second blower and a power splitter, I inferred you were interested in the second of the three I had posted. That particular dual blower design does reduce the Y-axis build volume, and I wanted to make sure that you were aware of that difference. The two that I have tried do not impact the build volume.
http://www.thingiverse.com/thing:1542849 dual rear uses existing blower
http://www.thingiverse.com/thing:1695189 dual rear reqs 2 x blowers on back
http://www.thingiverse.com/thing:1716089 Single, uses existing blower, improved ductwork for left blower