It could only be done on the front wheel as the rear hub precludes this. This is a very viable option concerning a front mounted electric motor. Another option would be
www.cyclone-usa.com. Jim, the owner there, had made a mounting bracket just for Downtubes (last year's model) and may work with this one. They have a wide variety of kits starting at $400 plus batteries.
I personally have ridden bikes equipped with their motors and was very impressed. They have more powerful motors than the Bion-X but no regen capability which isn't that important to me. I have ridden the Bion-X system as well.
In reality the SA internal 8spd hub would be an ideal candidate for one of the Cyclone-USA systems. In reality one of their 500W motors would push you about 20mph on the VIIIH. I am currently testing on of their kits on another bike and was looking at fitting it on the VIIIH as it would be a great match. Since as delivered the VIIIH has slightly too high of gearing, the electric motor would help out a lot on climbing hills and with the higher gear range it could push you along at a pretty good clip too.
You could add one of their kits and go with sealed lead acid batteried (SLA) and have a bike ready to roll for about $500. If you go with NiMH or LiON batteries you will spend more but have less weight. Give Jim a call or write him and he'll be glad to help. Really helpful and he knows his stuff.
It would take you about an hour to install one of their kits if you are semi-handy with tools.