Have you Spender or anyone looked at the GNU Hurd microkernel and server programs?
Are they more secure or do they have bigger issues than the Linux kernel does?
They say cause the servers run in userspace under non-root users that they would be more secure (at least in terms of affecting other parts of the system).
Some links about the advantages of the Hurd microkernel system:
http://www.gnu.org/software/hurd/hurd/advantages.html
http://www.gnu.org/software/hurd/hurd/what_is_the_gnu_hurd.html
http://www.gnu.org/software/hurd/mailing_lists.html