I've always had a fascination with mixte frames. I remember the first time I looked seriously at a twin lateral design and how impressed I was with it even though the frame I was looking at wasn't much to speak of. There are surprisingly few custom mixte designs on the road.
This mixte is very traditional aside from the curved stays and their attachment at the rear of the frame. It solves a problem common to mixte designs involving chain clearance around the extra set of stays. I like the look of it as well. Reminds me of the finger wave hairstyles women wore in the 20's and 30' s. A lot of inspiration came from a mixte built for last year's Cirque du Cyclisme by J.P. Weigle and a Charrel mixte in the Golden Age of Handbuilt Bicycles.