They've been announced, within the past two weeks, and as far as I can tell aren't actually available for purchase from retailers yet: the only thing I've seen actually purchasable is Crucial's 6400MT/s CUDIMMs, and Newegg has an out-of-stock listing for a G.Skill kit rated for 9600MT/s.
The linked Geekbench result from August running at 7614 MT/s clearly wasn't using CUDIMMs; it was a highly-overclocked system running the memory almost 20% faster than the typical overclocked memory speeds available from reasonably-priced modules.
