Install NetBSD (or any PV-capable system) on IBM's SoftLayer

At ${DAYWORK}, I happen to use IBM’s cloud: SoftLayer. It has all the features you’d expect from such a platform, and can instantiate pretty much any major GNU/Linux distribution you’d think of; but here’s the thing, we also use NetBSD for some infrastructure services, and as you’d guess, there’s no NetBSD support at all on SoftLayer. I had to reverse some bits of their provisioning system to understand how to achieve NetBSD installation, but most of all, automatic provisioning.