Quad FX will only help in certain apps and it'll be quite expensive.
Right around the time1333-1600MHz DDR2 will hit.
No official support.
I say FX but K8 was always meant to be quad. That would really start to saturate the DDR2 bus. Without K8L. I hope to see signs of it soon. 8x8 won't be K8L and the news from AMD says Q1 or so(ABC news).
SLI RAM is being standardized by JEDEC. Corsair is already running at 1200(Corsair). OCz probably is also. Haven't been to their site but both are SLI RAM partners with nVidia.