I've run into this charming floral smock here and there on the internet; it's from an Etsy shop called Dottie Angel. It's not currently available for sale, but I thought it would be fun to put one together myself.
For a jumping-off point I used a simple, over-the-head sundress pattern with side ties. Since I wanted short kimono sleeves (or wide cap sleeves: I'm not sure where you draw the line), I laid a different pattern over the shoulder to get that in place. Then I picked out a large pocket from an apron pattern, and put it all together.
The smock works because of the careful placement of the casings. In the front, there are two casings for the drawstrings, and they are out towards the side seams. In back, the casing is centered across most of the dress. Keeping a smooth front is so much more flattering than gathering all the way across the middle.
You can see that I added a center back seam so I could make a sway-back adjustment and remove the extra fabric from the curve of the back. I used bias binding to finish the neckline, and narrow-hemmed the sleeves.
This makes a sweet and perky housedress!