Pattern used was Truly Victorian 201: 1870s Underskirt. Fabric is three times dyed 8oz linen from Dharma Trading Co. The three tries at dyeing was because I was at first trying to match to the polonaise purple, then when that didn't work, match to the maroonish bits of leaves on the polonaise, then the 'screw it all, I'll make it brown" when I tried to match it to the linen trims on the polonaise. Obviously, none of them worked. But the depth of color ended up being something I was really pleased with. The brown gave it a nice 'weathered' look to it, something that I appreciate in historical recreations. In most cases, I don't WANT to look like I'm wearing something fresh out of the box.
The false panel of pleats was fairly easy to assemble. I just took as long of a rectangle as I could cut out of whatever fabric I had left over, hemmed one end, then pleated it an arbitrary width of knife pleats. The pleats were sewn together on the machine at the top, then the back portion of each pleat was sewing with a very narrow hem to help the dress hold it's pleats, even when the skirt has been traveling. Even if they're not crisp and freshly ironed, they'll at least not have fanned out like a train and lost all pleating.
The belted portion trimming the top of the pleats is just a length of brown velvet folded in on the sides and one ends. It's sewn down to the skirt on the top, then tack stitched to the edge of each pleat on it's bottom edge. I wanted to give the impression that it was the belted bit that was holding in the pleats. The pointed end was left unanchored, except for a single button to help aid in the illusion.
The entire skirt is hemmed with narrow strips of velvet that were folded and topstitched at the top and bottom to give it the impression of being velvet ribbon. WAY cheaper than using actual velvet ribbon.
The complete outfit. I had to go back and tack up the skirt on the polonaise a bit more in order to see the belted bit at the top of the pleats, but bustles are good about accepting that. I'll try to fiddle with it so that the skirt of the polonaise hangs lower on the left side. I'm aiming to wear this to a steampunk tea in December, so that's motivating me to get a few more cold weather accessories out to go with it. There's a fur muff in the works, and I'm toying with the notion of trying to draft my own pattern for a talma wrap of some sort.