I am just in process of electrifying a big dummy.
I decided against the bionX system as I felt it was pretty expensive for what you get. I'm sure its a good reliable system but I wanted more bang for the buck.
I ordered, but have not yet received, a front hub motor system from Doug at www.gocarlite.com
who is in the bay area. The wheel is made by www.ampedbikes.com
, and is a pretty good price and gets good reviews. It is a geared hub motor, vs direct drive. direct drive has continual small resistance when pedaling which I found unappealing. also direct drive hub motors are insanely heavy.
The system I'm looking at is a 48V lifepo4 high end battery pack with more than 1Ah charge, a controller, two chargers (one for home and one for work) thumb throttle, and front wheel (26") with geared hub motor for about 1k. I like the system because it is adaptable and doesn't require you to purchase a branded product.
hope that helps.