hmm ,I searching on internet ,and no many in USA. I saw one on Ebay ,one American selling some ytong. All is in EU ,many in my country and in Germany. The best company who making ytong I think is Xella ,good quality. I think ,in USA you have other materials and practices for building houses (wood ... ) - it is the capital problem ,your country maybe dont need ytong and maybe Y-tong material is "patent" by some company in EU ,and they dont want to sell that build patent for US industries. Try to find some info in US local build-shops or show them picture of ytong ,maybe in USA it has only other name
Skippy