Is there any chance the system-config-netboot* rpms upstream removed from CentOS6 could be provided in extras? The CentOS5 SRPM builds cleanly under CentOS6, and upstream's workaround is insufficient as it only covers diskless clients, not helpful if you need pxeos. https://access.redhat.com/knowledge/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Storage_Administration_Guide/nfs-diskless-systems.html