… and Ubuntu 11.04 has an every so slightly broken root on iSCSI …

Православни икониUgh. See here. Got bit by this.
BTW: The new internals of Tiburon are getting even more wild. This thing is turning into a very powerful system for booting large numbers of machines with (nearly) identical configs, very quickly (hmmm … can you say … cluster? Cloud? VMs? …. mwhahahaha!).
Will be re-adapting our menu system for this, but the Web GUI portion for configuring this is definitely in the near future.