NodeOS
Build script
The build scripts on https://github.com/NodeOS/NodeOS-Docker seems really easy to understand, so it would be possible to use them as basis for a build script that creates a Raspberry Pi .iso image ready to flash. It could also has options to create a QEmu virtual machine and launch it, maybe a makefile following the same steps that Docker build is a good start.
I really like this idea.
This is low-priority for myself right now, but I would greatly welcome a contribution here, and I am more than happy to help out.
I used qemu to work on this the first time as well. You have to develop on Ubuntu however, if you want the filesystem to be ext4. Assuming you're on OSX.
Building full block devices with a build script is less than elegant, and you'll likely have to use a loop device.
Don't have too much spare time, but I'll look after this. I'm working on LinuxMint, so no problem here :-)
Instead of block devices, maybe we could use udev? This could be for a future improvement, though...
This is a pretty low-priority project right now. Unless you really want to get it working, I'd leave it.
I'm a bit fuzzy in this area, but I believe udev is a user-space process that dynamically loads kernel modules when new devices are attached to usb etc.