If I had to make it for you, I would make a white kimono from this pattern: http://www.folkwear.com/113.html
with sleeves about twice as long as in the pattern indicates (which I've done before so I know it's very doable). I would need to custom work that white collar. I would leave the white kimono in pieces.
Then I would cut out a black kimono from the same pattern but only let the body come down as far as the butt (give yourself something to tuck into the loose cotton pants). The white kimono pieces are then sewn over the black kimono, to allow for the gaps in the shoulder seams. The side seams on the white kimono body would not be sewn, to allow flaps all around the pants.
In terms of what material I'd make all this out of, that depends on your budget. The white kimono parts will take every bit of 5+ yards of material, the black maybe 4. If you insisted on the authenticity of silk, I'd recommend raw silk or something else with texture but not sheen. I'd rather see you in a nice cotton, cottolin, or cotton-rayon blend. I just don't think silk is necessary, no matter how authentic it would be.