I think this is where the idea of co-locating compute and storage really shines (eg: Joyent/Manta, scaleableinformatics.com) - moving all state to nfs sounds like a great way to widen the performance gap between RAM and permanent storage... Not to mention that if you really want to spread your data and your application, you would require nfs over vpn (unless encrypted nfsv4 actually works now?).