The sad thing about MPI is that it's entrenched. To run it on the biggest iron such as Blue Gene they have to use a mechanism called OS Bypass to get the bytes on the wire fast enough because the Linux kernel takes an age. One of the other teams in Sandia work on alternatives to running Linux; see their use of Plan 9 in "Using Currying and process-private system calls to break the one-microsecond system call barrier, Ronald G. Minnich, John Floren, Jim Mckie" - http://iwp9.org/slides/usecsys.pdf
However, obviously the actual users want to maintain their investment in their MPI based Fortran software so it's one of those situations where merely matching the current systems is not enough unless you can demonstrate heaps of potential.
The above article is from 2007 but the library here was updated in March 2010.
MPI is not dead. Point made?