Simple-CDD is a limited though relatively easy tool to create a customized debian-installer CD.
It includes simple mechanisms to create "profiles" that define common system configurations, which can be selected during system installation. Simple-CDD also makes it easy to build CDs with language and country settings pre-configured.
This can be used to create a crude "Custom Debian Distribution" using packages from Debian, with pre-configuration of packages that use debconf. Custom configuration scripts can be specified to handle packages that don't support debconf pre-configuration.
Testing CD images with qemu is also made simple with a provided script.