Hi,
Along with the Linux kernel, another interesting tidbit.
http://www.phoronix.com/scan.php?page=article&item=x_server_contributors...
"There were eight major software vendors that turned up from our analysis and that included Apple, Debian, FreeBSD/NetBSD/OpenBSD, Gentoo, Mandriva, Novell, Red Hat, and Tungsten Graphics. The biggest software company contributing to the X server has been Red Hat"
"In third place for the number of commits is Adam Jackson, an employee of Red Hat. Adam has just been committing to X.Org since 2004 but he represents over 9% of the total workload. Adam Jackson is serving as the X.Org 7.4 release manager."
Rahul