This company claims an alternative to ELC without draining or replacing your coolant and meets EC-1. It appears you just add this Final Charge, change out your coolant filter to a blank and your good to go 6 years or 600,000 miles.
Any words of wisdom from the brain trust?
http://www.finalcharge.com/converter.html
PS - A lot of folks on another forum have been using this for some time.