Inara wears this peach dress several times in Firefly.
More pictures after the break...
More promo pictures...
Screencaps, from Shindig:
From Out of Gas:
From War Stories:
From Heart of Gold:
This woman has an infinite number of robes, it seems. I'll link up the post of the corresponding robes when they go online. I know there are some caps of this dress somewhere in my robes folders and one cap up there doesn't even show the dress, but I know it's under there!
My Photobucket Album for Inara.
Serenifly Costumes site for Inara.