The best bet for this on unix is Window Maker paired up with WMfinder. A ppc version of the Window Maker RPM is available from ftp.linuxppc.com in the contrib directory for their latest release. You will have to download WMfinder from http://www.imago.ro/wmfinder and compile it. I'm going to see if I can get the linuxppc people to include an RPM for it in their next release.