The more things stay the same: distributed tuple space toolkits like Jini
Long ago at SAIC, my old Friend Tim Kraft (now doing great things at Overture/Yahoo) and I did a commercial product that was loosely based on David Gelernter's Linda data model. About 5 years ago, at Intelligenesis, we looked seriously at Jini-type models for distributed processing.
Anyway, I noticed that the new Jini starter kit is now Apache licensed which should allow what is a great technology (for some distributed data problems :-) to be used easily by commercial application developers. Worth looking at if you have never experimented with Linda, JavaSpaces, or Jini before.