More ATI partners are working on Radeon HD 2600X2 dual RV630 versions and the first samples will slip in Q4. We got the first words that the real working cards will be available in October and shortly after that in retail.
The samples will work as a single card Crossfire and quad driver comes later. This is the temporary path that ATI wants to follow at least until R700 is ready.
We will be able to tell you some estimates from two RV630 chips working together so stay tuned.