Following Luke and Jeffrey's suggestion, I edited /etc/X11/xorg.conf so
that the 'Unknown' monitor was replaced with 'Hitachi CM812' (which is
listed in the database 'MonitorsDB'), the known vertical and horizontal
scan rates were supplied, and higher resolutions were added.  In addition,
the color depth was changed from 8 to 16.  After a reboot the resolution
went to 1600x1200, but the color depth stayed at 8.  This may make sense,
because the video card can handle 1280x960 by 16-bit color, but with 4 MB
of memory may balk at 1600x1200 by 16-bit.  So far my attempts to reset the
resolution to 1280x960 have failed (I removed the 1600x1200 option in the
resolutions list).

I took a look at some of the files in the directory 'system-config-display'
and noticed requests to import various other files.  However, one of these
files to be imported, 'rhpl.monitor', could not be found anywhere on my
system (using 'locate').  The problem I'd described earlier: 'Okay' button
grayed out in the monitor selection list and complete inability to select a
monitor by the system-config-display route, persists.  Is it possible that
there is an essential file missing, that can't be imported as needed, which
could account for the recalcitrance I'm seeing?

Addressing my question,
>> - After booting, and invoking LVM (needs password), a window appears and
>>   immediately disappears.  What gives?

Troy Dawson had replied,
> What do you mean by "invoking LVM"?
> Are you selecting something from the menu?  Or are you typing in a command?
> 
> If you are selecting it from the menu, then try typing
> 
>   system-config-lvm
> 
> from the command line, and let us know what the error is when it stops.

Here's the output I got:

------ begin output ------
[dushan@localhost ~]$ system-config-lvm
Traceback (most recent call last):
  File "/usr/share/system-config-lvm/system-config-lvm.py", line 138, in ?
    runFullGUI()
  File "/usr/share/system-config-lvm/system-config-lvm.py", line 123, in runFull GUI
    blvm = baselvm(glade_xml, app)
  File "/usr/share/system-config-lvm/system-config-lvm.py", line 73, in __init__
    self.volume_tab_view = Volume_Tab_View(glade_xml, self.lvmm, self.main_win)
  File "/usr/share/system-config-lvm/Volume_Tab_View.py", line 117, in __init__
    pr_upper = Properties_Renderer(window3, window3.window)
  File "/usr/share/system-config-lvm/Properties_Renderer.py", line 69, in __init __
    color = gtk.gdk.colormap_get_system().alloc_color("white", 1,1)
RuntimeError: couldn't allocate colour
------ end output ------

Pure speculation: LVM wants a color that it can't get from only 256 colors
(8-bit), so dies.  If this is what's going on, the LVM problem is just a
consequence of the preceding one - my inability to pick monitor, resolution,
color depth, and refresh rate.  What could cause the 'system-config-display'
program to mis-behave the way it is doing?

- Dushan