Actually I saw yarns from thread to DK called America's best by Pisgah. Do you have a project in mind and if so what is the name of the pattern? A link would be helpful, too. http://www.elmore-pisgah.com/ambest.htm
When asking questions ALWAYS post the name and a link for the pattern if you have it.
Any yarn that would use the same size needles and get about the same sts per inch as the pattern. America's best is sort of a brand made by the Pisgah company and has several different yarns that range in thickness or weight.