The first two bullet points make me uncomfortable. "Declarative tier splitting" sounds a lot like a movie I saw during the COM+ days. In that movie a hero by the name of "Location Transparency" was killed by 10 million chatty microbes from the Andromeda galaxy. It was a slow death, and a sad ending.
Two things sparked my interest in Volta, however. Seeing Erik Meijer at the helm of Volta was one, and MSIL rewriting was the second. There are MSIL re-writing tools available today (see the profiling API and Mono.Cecil as examples), but mainstream MSIL re-writing can bring many benefits to the CLR. One only has to look into Java land where bytecode modifications yield interesting possibilities for aspect oriented programming, inversion of control scenarios, application optimizations, and more.
... much closer to the model I was looking for, and it works in IE and FireFox, too.
It will be interesting to see how project Volta progresses.