Post 30 says they're only doing yellow and blue so far. That doesn't mean they couldn't make top-quality white diamonds, of course ... maybe they can't, or maybe they're not ready for that market yet.
They already do. I've seen Russian synthetics in red, blue, green, white and other colors/shades. In addition the colors of certain natural diamonds can be altered by zapping them with nuclear radiation or high pressure-high temperature (HPHT) techniques...that's where all those colored diamonds they sell on the shopping TV channels come from. A good number of "brownies" that range from dark brown to light as well as into the "fancy" champagne, yellow and orange colors occur naturally in Australia. They're marketed in the U.S. by Argylle Diamonds.
Most "black" diamonds which are so popular now are nuked. Beautiful pink and red diamonds are found naturally in Australia and elsewhere, and are among the earth's rarest and most valuable treasures.
Why not just buy paste? It comes in pretty colors and is cheap.