NV News reports that Uttar has picked up some solid information on Nvidia's NV36 GPU, and here it is.
Made by IBM, 0.13u process, 82M transistors, 500MHz core clock
256-bit memory bus, 325MHz RAW memory (probably 128MB & 256MB versions)
Marketing claims that the NV36 is twice the NV31 (as they did with the NV35)
Half the shader pipes of the NV35 (FX 5900)
Apparently it will be branded the GeForce FX 5700, and whilst it taped-out sometime during May, general availability is still unknown.
Source: NV News