Well, on the website you'll find the phrase "Price depends heavily on volume purchased". That tells me that, unless we're Intel or Motorola, we won't be able to purchase any. Unless we get a huge group buy thing going.
"While offering nearly the performance of diamond, Black?Ice? can be fabricated at about
4% of the diamond cost."
edit: From reading the materials, it doesn't sound like it's something appropriate for use in heatsink applications. Cost prohibitive is key, given that it's intended for use as substrate material in IC's and stuff.