I tried out a tuck pattern that I thought might give the same sort of look. Normally, you use the purl side of a tuck pattern for the right side, and although it did look nice in it's own right, it wasn't the look I wanted. It was a little more blended.
I used Headwaters Wool in a beige lace weight (what I used for my Flowerbasket Shawl), and Tanis Fiberarts Pink Label Lace weight that I used for my Sweet Lily Shawl. After I was done, and searching for a better yarn to sew it up with, I found a brown sock yarn that I had actually intended to use for these...the brown yarns are very similar! I thought it would be neat to make the ribbed cuff be on the inside only. I think it turned out exactly like I wanted! For the inside mitt, I used a standard increasing thumb gusset, using my three prong tool. But, I didn't think I could do that on the outer mitt because I didn't want the tuck pattern to get messed up. So, I put markers on the edges as I knit the outer part, where I wanted the thumb gusset based on the measurements of the inner mitt. Then, I did the thumb gusset like I showed with the two-toned purple mitt--picking up one stitch on each side, every two rows...
The math didn't work out exactly, given the nature of tuck stitch, and I had to space the 'increases' out to get to the full height of the gusset. As I was doing this, I was thinking....if I had taken an outline of her hand while there, I could have drawn a pattern to use in the knit contour! Then, I could make mittens when ever the mood struck me! The thumb gusset looked a little misshapen on it's own, but seemed okay once I tried it on.
The other idea I had, was that I could have knitted these from the outer tip down to the cuff, then re-align it on the machine to make the inner mitt circularly. That would have been good given the fragile nature of the single ply beige. You can't go from knitting circularly to knitting rib though, which is a bummer, but I'm sure I'll have other mittens I can try this out on!