Try network boot. Setup a pxe environment and you should be good to go. Another solution is use debootstrap to install Debian or Ubuntu to a plain directory. B

Try network boot. Setup a pxe environment and you should be good to go. Another solution is use debootstrap to install Debian or Ubuntu to a plain directory. Be aware that you have to make some adjustments to the system (like installing a bootloader/kernel/adjust fstab etc.) after executing debootstrap. You can also use grml-debootstrap which automatically executes the needed steps to make a system bootable.