Broke down and made the Regency gown. I used Simplicity pattern #4055, view A for myself, and I made it a size - hah - 18 to fit my bust. I'm not an 18. I'm a US 14. I read somewhere a mother lamenting that patterns ran big, which thoroughly surprised me. My friend and I have sewn dresses together for years and it has been our rule of thumb to size up a pattern. Amanda is tiny compared to me, I mean tiny, and she usually sizes up, not down when sewing from a pattern. Like most Simplicity patterns I've encountered, I sized up. And to my chagrin, after hours of labor, discovered this baby still didn't fit. Unless I wore my stays. Which are totally the wrong foundation garment for this time period. Stays = French and Indian war and the Revolutionary War. Stays don't = Jane Austin. Fail.
Also disconcerting about this dress - total lack of placket to cover the back. The instructions were to create a drawstring casing around the neck line and the bottom of the bodice to draw the dress in. I will certainly be doing a little aftermarket adding to this garment, because no where, in the history of Regency clothing, was it socially acceptable to have what you wore under your dress on display to the public. I was pretty well covered but mollified nonetheless to discover that the back gaped if I did anything other than stand stock still. I realize Simplicity patterns aren't completely historically accurate. They've got the general shape going for them and the bit about tying in the back. But I'm pretty sure there should have been a placket here. I wore a similar gown to a dinner party once that buttoned in the back instead of tying - my friend had to adjust the internal drawstring on the bodice and replace the buttons so that it would fit me, but my friend's back would have been sufficiently covered by a placket had she been wearing it.
I did also make one to fit doll, out of the scraps from the dress for me. I used American Girl's Josephina's Christmas dress from the Pretty Clothes patterns, and omitted the long sleeves. Have I mentioned something about patterns running small? Oh, right, because it seems the pattern drafters at Pleasant Company had difficulty with this concept as well - the dress doesn't fit the doll! I made some bias tape to bind off the sleeves on the doll dress instead of making the sleeves long, and will have to use additional bias tape to make a Velcro placket for the back, and to bind off the hem so that the dress is the proper length. Details. Details I shouldn't have to worry about, because I followed the directions to a T and they still don't fit.
I used Halloween as a road test for the dress, wearing it at work before I wore it to a party I was invited to. I was invited to a birthday tea party, and the instructions were to bring along a doll or bear, so I brought along doll in her dress (mine was packed so I wore something else). Huge, huge hit. :)