Even the big Kingston has problems in supplies of 2x2048 popularly known as 4 GB kits. It informed its partner that the memory should be available but we failed to find it in the European or the US etail market.
The company has a cool kit with 4096 MB of PC2-6400U memory with great timings. This memory will work at CL4-4-4-12 and of course we are talking about DDR 2 800.
Kingston product number for this kit is KHX6400D2LLK2/4G and it should be available soon at €450 price range. It is interesting to say that not even Newegg or Tigerdirect in the US have it.
It should be available in Q2 that starts in a week time but it's good to know that something like this is coming. You can check the kits here.