I found this one: http://archive.org/details/SamuelThibaultOnGnuHurd
GNU Hurd should provide extensibiltity from the ground. But many things (such as sound) are not yet implemented yet. The Hurd uses the GNU Mach kernel, which still uses Linux 2.0 drivers. The only way to get SMP, ACPI, sound, 64 bit is to run it side by side with GNU/Linux-Libre using xen.
