You might want to look at the bottom of http://www.osl.iu.edu/research/pbgl/documentation/graph/index.html
"Parallel Processing Library" http://www.osl.iu.edu/research/pbgl/documentation/parallel/ referenced there is exactly "a higher level framework for distributed computations" I suggested you to look at. Unfortunately, it offers very little additional abstraction over raw MPI2 C++ API so it's advantage is doubtful. I thought of library which offers more specialized work flow concepts. For example, often a distributed environment is used just because there are a lot of data to be processed, and each piece of data can be processed completely independently or without major cooperation between computational nodes. Examples are video rendering/processing (if it's not I/O bound), distributed C++ compilation, SETI@Home/other BOINC projects. Such tasks fit a model which I call "std::transform with a stateless functor". MPI has abstractions for this (like MPI_Scatter/Gather) but it's very limited, ineffective and practically useless in many circumstances. Different node speeds, different and non-predictable amount of resources needed to process each data unit lead to node stalls. And MPI_Scatter requires an in-memory array instead of just an input, a past-the-end and an output iterator. Andrey