There's an interesting conversation between several Lisp machine folks (including the late Dan Weinreb) and Azul's Cliff Click. This was at a time when Azul shipped custom hardware. Very interesting, re: hardware support for garbage collection.
They did indeed ditch their custom hardware: the appliances were excellent, but not really a competitive proposition compared to "buy a cluster of commodity hardware and if one JVM instance goes for a coffee break, treat it as any other transient failure and route requests to another host."
I haven't looked in a really long time but wasn't Azul's focus running the JVM directly on the hypervisor? That seemed like an interesting approach vs using custom hardware.
