The rootfs of the setup for Blackhost 8.0 x86_64 was created using uclibc-buildroot version 2010.08 from 
http://buildroot.uclibc.org/ GPLv2

- buildroot-2010.08-blackhost.patch
  contains all changes done and the configuration for the root-fs of the x86_64 setup

- a binary of "file" is needed to build rpm 4.4.2.3 as the setup cannot execute the self compiled version (or LD* env), see patch

- next steps:
$ cd $PATCHED-BUILDROOT-DIR
$ cp BUILDROOT-CFG .config
$ make oldconfig
$ make UCLIBC_CONFIG_FILE=UCLIBC-CFG BUSYBOX_CONFIG_FILE=BUSYBOX-CFG
.. wait ..
Image is now in $PATCHED-BUILDROOT-DIR/output/images/rootfs.ext2

"setup" is missing in patch, but can be found in this directory on ftp.blackhost.de