[andrewf]

Starting with FreeBSD might be easier than starting with Debian then removing all the GNUisms. But perhaps not as much Type II fun.

[tssva]

Using Linux gets you much more hardware compatibility especially for the consumer desktop and laptop systems this is targeted towards.

[andrewf]

True

[dvdkon]

I think Linux is the better choice for replacing the entire userland. From what I've seen, the BSDs don't have such an accessible userspace/kernelspace split. With some effort, on Linux you could probably just run an exe as your init.