Interesting, hadn't seen that (have to read it in more detail later). Does sort of remind me of the approach taken to synchronization/managing time for Croquet[1]: Tea time[2] (although the aim there had nothing to do with live programming). Seems like a different need for managing time, but a not entirely dissimilar approach.
Thank you for the references. I've seen some of these before, but connecting the dots can be difficult (meaning, I have to keep going back to them later). A lot of seems to have gone into Kay's new project @ VRPI.
[1] http://www.opencobalt.org/about/history
[2] I think the paper I read is this one -- but I can't verify it from here:
"Designing croquet's TeaTime: a real-time, temporal environment for active object cooperation", David P. Reed http://dl.acm.org/citation.cfm?id=1094861
See also: http://www.opencobalt.org/about/synchronization-architecture