In a way this really doesn't need a blog post. It's not as fiddly as XEN was and if you are willing to just do everything through Glish it pretty much just proceeds as expected. But my concern was having to be reliant on Glish as until recently it didn't work on NetBSD Firefox (does now) and connecting via lish would give you a blank screen (not fun). But you can get both to work:

  1. Create three disks, 1x 1024 MB (ext) called "Rescue", 1x 1024 MB (raw) called "Install" and 1x the remainder (raw) called "NetBSD". An extra Rescue disk is required owing to the size of the image and unzipping it.
  2. Create a two configuration profiles, use Direct Disk, Full Virtualisation and turn off the FileSystem/Boot helpers. One has the NetBSD and Install disks mounted and is to boot from the Install disk in order to install to the NetBSD drive, the second is the final one which just boots NetBSD.
  3. Boot into Rescue mode with the Rescue disk first, Install disk second, etc.
  4. mount /dev/sda /media/sda and then cd /media/sda.
  5. Get the USB image, wget
  6. gunzip it and copy to the install drive dd if=NetBSD-7.1-amd64-install.img of=/dev/sdb.
  7. Boot the install configuration and within 30 seconds get the lish console open and press space to drop out of menu. Select 4 for the boot prompt, enter consdev auto, then menu, then press enter to boot; If you want to read about consdev it's in man 8 boot_console.
  8. For whatever reason it fails to automatically launch the install so login as root and then type sysinst to run the installer.
  9. Go through the install, on the bootblocks screen accept default of "Use serial port com0" and then under "Set serial baud rate" select 115200 for the baud rate.
  10. Shutdown the install configuration and then boot the NetBSD one. Hey presto! Glish and Lish work.

I still haven't converted my XEN install to KVM yet though, but might soon

[EDIT: 2017-06-26] Wow, if you want to play with NetBSD 8.0 Beta then you might as well double the Rescue and Install images.