XFS download mirrors:

SGI-released packages and patches

oss.sgi.com also has an rsync server:
rsync://oss.sgi.com/xfsftp/

Jan H. Schrewe's mirror in Germany:
ftp://ftp.mpg.goe.ni.schule.de/pub/linux/kernel/xfs/sgi

Denmark mirror:
ftp://sunsite.dk/mirrors/xfs/

Netherlands mirror:
http://mirror.math.leidenuniv.nl/oss.sgi.com/

Full install mirrors:
ftp://ftp.thebarn.com/SGI/

Australian mirror:
http://planetmirror.com/pub/sgi-oss/xfs/
ftp://planetmirror.com/pub/sgi-oss/xfs/

French Mirror at Ecole des Mines de Paris:
ftp://ftp.cma.fr/pub/mirror/system/xfs/

Contributed Packages

Mark Pinto has kindly provided Debian packages:
http://www.markybob.com/xfsboot/

XFS patches are also available in Debian-unstable ("Sid")