I've packaged a number of X11 window managers for Solaris. In all cases these have been built to install directly into /usr (or in the case of the twm variants, /usr/openwin), so they're in the normal path. They have no horrific non-standard dependencies, as far as I know, so each one is viable alone. I've provided login integration for both dtlogin and gdm. The packages will work with Solaris 10, update 5 (or later, and possibly earlier), and also with OpenSolaris or OpenIndiana.