While the high-end NVIDIA D8E is expected in January 2008 we'll have to wait a bit longer for NVIDIA's next-generation GPU.
According to FUD Zilla the firm's next-generation GPU is called D9E and will arrive in Q2 2008 or later.
This matches the Nvidia's financial conference call where one of the Vice presidents said that Nvidia will have at least two new high end product until the next analyst call. This one usually takes place once a year.
D8E is a dual PCB dual chip card while D9E is a new chip that we don't know much about. We know it will be much faster than G80 but that is about it. In 2008 the graphics boys can do 55 nanometre and it will be too soon for 45 at least we think so.