One interesting development: I finally found a decent process-shared memory heap manager, with a friendly BSD license: AppleSeeds (part of Grail). Which gave me cause to refactor things a bit to support pluggable storage mechanisms. Which, in turn, means Thread::Sociable will (eventually) support both thread *and* process shared variables, including for STM, and in the same app (via a weak 2 phase commit operation).
Another interesting development: I'm sitting in the pthreads tutorial at the moment, and turns out Intel is announcing something important at the tutorial I'm attending tomorrow, and it may provide an STM implementation. Of course thats only working for Intel (and AMD), but if its FOSS, it might be portable. Should be interesting, and might be a nice candidate for Thread::Sociable.
Hopefully, I can find a nicely open source DSM soon. Then things should get really interesting.