A minimal chroot supporting extension via apt-get;
vitals if built on Sisyphus as of Jan 16, 2012:

  i586: 13M tar.xz, 58M chroot (33M w/o /usr/share/{doc,locale,man})
x86_64: 14M tar.xz, 60M chroot (35M w/o /usr/share/{doc,locale,man})

Trivial fixups (extra checks) added to two script hooks.