Hello Stefan,
Roland, to your question, I am not sure which major problem you mean regarding the MPI process, but I have made test how to couple SPH with a grid based background and how to take advantages from the grid.
Basically the issue that Matt Kinsey mentioned in his email.
I am afraid I could not call in into today´s ET phone call.
The call is currently going on. As far as I know eg google voice lets you call the number for free (+1) 225-578-4942 SKype will charge you I think.
Yours, Roland