Oops...nevermind...there was a bike shop in Missouri but looks like he moved to Texas.
You can put one together on your own for about $600 - $700 that's probably even better than the one you mentioned. I wouldn't buy it. Get a kit online and then maybe pay one of the teenagers in your neighborhood to put it together or something (If you don't want to put it together).
Is 14 mile range good?
You could buy a kit from either
ampedbikes.com
e-bikekit.com
hightekbikes.com
then buy a 36v8AH NICD battery from
http://ebikes.ca for $240 and put it all together. And it'd be about $600 probably. Much cheaper than the Giant Twist bike. If you want more range, you could buy two of the batteries. That'd give you 28 mile range.