Foof! I've setup most of a network root for the pi. Still to do:

• Install and configure dnsmasq on tayet ss a dhcp/tftp server.
• Setup ipxe so that the pi, when it asks tayet for a kernel, gets pointed towards the right place
• Find out how much of the iscsi client stuff I need to install on the pi. (Thinking, if the kernel has booted of the remote disk, do I need the client tools?)
• Dream about a shared read-only /usr disk
• Go though that all again, but this time with the USB stick (four times faster than the sd card, and I'm only doing the iscsi thing as a test/demo for Mythic)