Check the site below, scroll down to Colonial Swag, if that is what your talking about yes you can add a casing and drawstring..
When drawn would create the fishtail look, they probably need to be cut on a slight angle to define the look..HTH

Here is a link that might be useful: Colonial Swag

That's what I am looking for, but I can't find a pattern. I'm thinking of taking newspaper and drawing it out and maybe making a muslin pattern. Heaven knows I have enough scrap material around here to use.

Judy, Good Idea on making a muslin..
Have you ever seen the sewing with nancy videos?
They have covered several subjects
When you open the site below the black box it has a list of 64 various videos, Pam Damour (they call her the home decor diva) has several on valances, swags and fishtails..

Sorry no not know exact numbers.

Although she is selling something just watch a few how she connects them, think you could just make your own.

Hope you show us what you come up with..

Here is a link that might be useful: Pam Damour Windows