The Neufbox 4 is a BRCM63xx based DSL router the french ISP SFR (http://www.sfr.fr) provides to its customers, and more than 3 million units are currently in use. The device is developed by Efixo (http://www.efixo.net) and the OpenWrt based sources are available through a subversion repository and documentation is placed in a Trac wiki (http://dev.efixo.net).
Efixo has shown a commitment for openness and have in the past been providing development sources (http://www.efixo.com/neufbox4/freesoftware).
Some sources are not directly available, but proprietary binary drivers are downloaded and integrated in the firmware during the default build process. Now, everyone can checkout the OpenWrt based sources, compile and install a firmware version which includes complete services, such as VoIP and television.
~$ svn co http://svn.efixo.net/trunk/ neufbox
~$ cd neufbox/
~$ make nb4-main
Further details (mainly in french) is found in the unofficial Neufbox 4 community (http://www.neufbox4.org), which offers information on how to build a serial JTAG, reflashing the Neufbox 4 and more.