[swaits]

Debian userland on top of the FreeBSD kernel? Was there demand for this? Or, was it primarily to sidestep the GPL stuff and incorporate ZFS?

[js2]

I suspect a developer had an itch to scatch. See http://wiki.debian.org/Debian_GNU/kFreeBSD_why

[dman]

Thats how Linux started :)

[effigies]

Yes: http://www.nexenta.org/