Hello, For information, I submitted a couple of fixes for the unreleased distribution in debian-cd, it now behaves fine when setting UNRELEASED=1 in CONF.sh: it includes packages from the unreleased distribution in the sid distribution of the CD. Also, I switched to using LOCAL=1, LOCALDEBS and UPDATE_LOCAL=1, which is indeed enough to select any few packages from unreleased for the bootstrap part.
Samuel