As you know, I am sworn to secrecy on these things. However, I make two observations based upon experience and not secret knowledge...
1) A bigger R9 wouldn't really be an R9, and would be a new model that would create many of the same problems as introducing a new R45 model.
and
2) A .40 caliber pistol would not, by definition, be an R9 -- it would be an R40. For the record, I have never heard the R-bros speak of an R40.