Sorry 'bout breaking threading.
Paul, you write:
The gPXE bootloader can fetch files from an arbitrary network host using TFTP, NFS, HTTP, etc, but the standard syslinux PXE bootloader cannot.
On CentOS 6, the syslinux-nonlinux package includes both. If you specify "filename gpxelinux.0" in your DHCP setup, and ensure that the gpxelinux.0 image is in your tftp root directory, you should be OK.
Are you saying that I only need to change the dhcpd configuration, from allow booting; allow bootp; filename "pxelinux.0"; <...> to allow booting; allow bootp; filename "gpxelinux.0";
and have my menus called by pxelinux.cfg/default point to the http://myurl/images?
mark