Wintron XC30 has had excellent results in Europe and appears to have some data to back it up. The big problem for most people trying it is lack of availability. I just found a company in Canada that distributes if for North America: http://www.celticpower.ca/page18.html
Most additives I have used claim "biodiesel friendly" on the front label and then tell you it is only good for up to B20 on the back - and even then at 2-3X the normal concentration. I might give the Wintron a try. It does not normally get very cold in Western Washington so I would only need .1% concentration. I only had cold filter plugging once in the 4 years I have used straight B100 in my truck - which often sits for long periods of time - and that was last week: It was 16 degrees. My Jeep Liberty CRDs have never had any issues because I plug in their block heaters, drive them daily and mix in some kerosene when it gets really cold. The problem will be when traveling to the East side of the state where temperatures are 20 degrees colder in winter....that is when I need a really good additive. Since I bulk buy my B100 in 600 gallon qtys for my fuel depot shed I would like to mix everything properly to begin with so I don't forget to add it when it is really needed....which is what happened with the truck. (To fix it, I plugged in the block heater, purged the lines and changed the filter. No big deal, but should have been avoided)
Cut your hair. When Joe & Jane 6-pack lose their fear of alternative energy and realize it's not just for hippies any more, dramatic change will occur.