Having never heard of colorshift yarn and being most inquisitive, I googled and found that it is basically a combining of yarns in gradations from one color to another--thus colorshift--working with a series of yarns that progress through the hues that make up the two "end" colors.
The Colorshift Shop on etsy has several yarn kits for sale, starting at just over $50, with the top of the line being the one you mention, the Bosphorus kit at $205. It is indeed a beauty and contains 2640 yards of fingering weight Merino Superwash yarn, but no pattern; you must obtain the pattern from the designer.
It will be interesting to learn if anyone has used the yarn yet.