I've created a pull request to update scalapack and remove blacs, as I describe here:
https://bitbucket.org/petsc/petsc-dev/pull-request/1/scalapack-update-to-202-and-remove-blacs/diff "In my never-ending goal to simplify dependencies with-in PETSc's use of external libraries, I have updated scalapack to 2.0.2 which removes the need for BLACS. I've tested this with --download-{scalapack,mumps} and also with my own custom install (which included a hand-built shared library of MUMPS and ScaLAPACK!) This pull request is mainly to test out the bitbucket feature and to get feedback on the forced renaming of SCALAPACK.py to scalapack.py (see the commit message for more details)."
