There was talk about the BBJ3 (752) and I believe Boeing is studying the possibility of developing this aircraft. I personnally would love to see it happen. However, with the economic downturn, it is unlikely that Boeing is persuing the BBJ3 at this time.
The C-32's owned by the US government are simply modified versions of the 752. They are not BBJ3's. Unfortunately. It sure would look sharp with those blended winglets.
I'm not a real aeronautical engineer, I just play one on Airliners.net.