More than once I thought it'd be cool to have each in-flight message assigned to a separate thread, dispatched asynchronously when you don't assign the message response to anything (or in the same thread as the caller when not), and see how it goes on processors with hundreds of cores.

I'm sure some post-grad somewhere used this to procure a monster workstation.

You sound like talking about https://github.com/smarr/RoarVM

    RoarVM, formerly known as the Renaissance Virtual Machine (RVM) is developed as part of a IBM Research project to investigate programming paradigms and languages for manycore systems of the future. Specifically, this VM is meant to support manycore systems with more than 1000 cores in the future.

    The RVM was open sourced by IBM Research under the Eclipse Public License. Please see the open source announcement for further information.

    Today, the RoarVM supports the parallel execution of Smalltalk programs on x86 compatible multicore systems and Tilera TILE64-based manycore systems. It is tested with standard Squeak 4.1 closure-enabled images, and with a stripped down version of a MVC-based Squeak 3.9 image.

    The RoarVM provides parallel execution of Smalltalk processes and thus, the programming model is a typical shared-memory model similar to Java with its threads and classical Pthreads for C/C++.