My dear, how about a hemp/polyester blend, in charcoal? It such a dark gray that it's almost black. It takes a crease, it doesn't wrinkle and it's got swish and fantastic drape. The only downside is how much it costs, but then, how about your labor, huh?

http://www.nearseanaturals.com/item.php?id=1542

Also in indigo

http://www.nearseanaturals.com/item.php?id=1543

Concerned about the weight? That stuff is 16 oz per yard. I LOVE LOVE LOVE that material.