You're right, it's X11 that's in charge of cursors. (As it turns out, the "nice little white-edged blue arrow" I mentioned is just part of Redhat's Bluecurve theme.) Thanks for the link, that led me to figure out how to change them. In case anyone else cares to know, they're managed by Xcursor (see the man page). "xcursorgen" can make cursors, even animated ones, out of ordinary PNG's. The cursors themselves are stored in the "cursors" directory for a given theme (as
freedesktop.org describes them), for example, /usr/share/icons/Bluecurve/cursors. Now if I can just figure out how X decides which theme to use (seems like it just looks at the "default" directory)...