So does anyone know where can I find this Start Screen background showed up on Microsoft Surface 3 tabled ?
Looks nice. It reads "Surface", so maybe it comes with the Surface Pro 3 as a custom theme wallpaper? If yes, we can hope for a "leak". Otherwise, it seems to be some inhouse work made for the presentation, maybe even based on a paid image (the loops) from a third-party. You could try your luck and search the web for it, but if it's commercial artwork, it'll be hard to get your hands on it.
Sorry i don't know how to get the picture,maybe you can find it through google. BTW,Surface 3 looks very like IPad