rootstrap

"A tool for building complete Linux filesystem images

Rootstrap was originally written to provide a facility for building filesystems for use with User-mode Linux, but can be useful in other applications as well.

It uses a modular set of shell scripts to create the filesystem image, install a base system, and customize it for a particular application. Currently, it only builds Debian systems, but the architecture is such that other base systems could be used instead.

Use of rootstrap does not require root access, or special privileges of any kind. This is because it builds the filesystem inside a User-mode Linux system running under an unprivileged uid.

Filesystem creation with rootstrap is quick and painless. With a local mirror and a single command, a fresh Debian filesystem can be created in about 3 minutes on relatively modest hardware."

http://packages.debian.org/source/rootstrap