Yes, I did.
I went back to the fabric store, bought the rest of the red silk, and made up another nightgown.
It's not as heavy a silk as the charmeuse - if there was "handkerchief silk" I'd call it that. I doubt it will last as well as the turquoise, it was half the price though. There wasn't enough fabric to make the little sleeves (sleeves take a surprising amount of fabric) so I found a pretty ribbon and attached it to the gathers instead.
Very simple construction, a nice addition to the wardrobe.
And now the existence of the red silk sitting unloved in the fabric shop won't keep me up at night. ;)