My apologies for an incomplete bug report; I worked around the problem before recording key information, and I am unable to repeat it. Essentially, while upgrading my Red Hat 6.2 installation to the Pinstripe beta, I left my computer during the RPM installs, and returned to find that it had stalled on one of the kde packages. Switching VTs to the bash prompt, I discovered that the program "desktopconv", running under my most- often used non-root user ID, was taking 98% CPU time and generating intermittent bursts of hard drive activity. Killing that PID caused the installation to resume immediately.
Probably related: After the upgrade, my home directory now includes (all real directories, not symlinks): /home/roystgnr/.kde/Desktop/roystgnr/.kde/Desktop/roystgnr/.kde/... etc, continuing probably out to MAX_PATH.
fixed