This tutorial explains how to install Debian Wheezy (testing) with the help of debootstrap from a Grml Live Linux system (like it is used as a rescue system at Webtropia). This should work - with minor changes - for other Debian and Ubuntu versions as well. By following this guide, it is possible to configure the system to your needs (OS version, partitioning, RAID, LVM, etc.) instead of depending on the few pre-configured images that your server provider offers.