I've done that a couple of times now. I don't really know when I started it. It's not like I don't have ideas of my own... Maybe it is just one of the lures of pattern making: It's so easy to follow the observation "that is pretty" with "I could make that". Of course, really making it isn't always as easy.
In this case, the jacket was a bit of a struggle. I agree with everyone who said that it was likely a one-piece pattern which should be draped to get that interesting shape. However, I only have one of those standard, adjustable dummies which does not really have my shape. And, most importantly, it hardly has shoulders (that is fairly common among dressmakers dummies and I consider it a big issue). I also don't have a human body double or a greatly talented draper at my disposal. So, I couldn't try draping. Flat pattern making was the only way.
After my "toiles" post, I actually made another raglan version with a two piece sleeve which curved forward a bit. Although it went some way towards getting that forward slump, it didn't really do the trick. In the end, I thought it edged towards being over-engineered.
So, I went with the half-kimono sleeve version.
I didn't use interfacing in the sleeve hems. I agree with those of you who mentioned some serious reinforcement would be need to make them stand out like that but I want to be able to wear this in real life, not just have it as a show piece.
The dress was much simpler. I made a skirt with six gores, slightly tapered at the front and side seams, flared from mid-thigh at the back seams. This also allowed me to put some real waist shaping in the dress, something you often loose a bit in patterns for knit fabrics.
To avoid bulk, I made the bodice from some fairly thin viscose jersey and finished its edges with fold-over elastic (used with the matte side out).
To keep and enhance the before mentioned waist shaping, I put a short invisible zipper in the side seam at waist level and made an inner waistband.
That waistband is just a piece of soft elastic which closes with a lingerie hook-and-eye at the same place as the zipper (the left side seam). I determined its length by measuring the waistline on the pattern pieces and tacked it in place on each of the vertical seams. The effect is subtle but it works. And, to my surprise, it isn't uncomfortable. It is probably not recommended if you have a lot of soft flesh around the waist though.
I'm glad I kept going with this pattern. It may not have all the sculptural beauty of the original, I still think it captures some of that charm. And comfortably so. Who would have thought?