It is unknown what the G72 and NV48 are, but X-bit Labs suggests the G72 will be a GeForce 7 product while the NV48 may belong to the GeForce 6 family.
A mainstream version of the GeForce 7 architecture – with 12 or 16 pixel pipelines as well as 5 or 6 vertex processors – may offer performance similar to the current high-end of the GeForce 6 lineup, which may affect sales of graphics cards based on the GeForce 6800-series chips, which is something that is unlikely to make graphics cards makers, who already have appropriate chips in stock, happy.Read more at X-bit Labs