The change from 8800GT to 9800GT was close to an outright rebadge with the exact same clockspeeds. nVidia was rebadging it yet again to the GTS series (I think 240??) until consumer complaints kept them from doing it.
The 9800+ GTX is similar to the 9800 GTX with some minor clockspeed bumps. Then nVidia was at it again and rebadged it to the GTS250.
Now they are at it again with the GT210 series making it a GT310 series.
This is pitiful of nvidia to do this. I would definitely nominate them and creative as the top 2x rebadging kings!
PS: I could have some info wrong
Jason