Are you after a knit or woven fabric with stretch? Where I work we have a fabric called stretch poplin which is a cotton lycra blend but is woven, it is like a shirting fabric with some stretch, there are some here too /www.fabric.com/SearchResults2.aspx?Source=Header&SearchText=stretch+poplin&CategoryID=1d5f47dc-9991-4088-93f3-26a376046a5e