I saw an image of this bike over at Bubble Visor so I did me some googling and found that it was also featured over at bikeexif.
It was built by a shop called Kraus Motor Co, who are based in Northern California and specialise in custom fabrication with a focus on the merge between innovative approaches and old school designs.
An amazing piece of machinery, it's as though that the rest of the bikes elements play second fiddle around the engine. The Harley engine is like the CBD, the hub, and the heart, with the tank and the seat organically moulding around it.
You can check out their website along with their other bikes here
(images sourced from the Kraus website)