Hi Aidan:

Well, I tried the version available at http://ftp.xemacs.org/contrib/cua-mode.el
And, it doesn't appear to do anything with respect to the Command-key.  And, reading
the documentation, it doesn't intend to either.  What I gather is that cua-mode imitates
MS Windows, because Copy would be \C-c.  Whereas on a Mac, Copy is Command-c.
So, the letter pressed is the same, but the Modifier key is different.  And, anyways,
cua-mode doesn't seem very attractive since \C-x and \C-c are such common XEmacs
keypresses.  What I have seen most MS Windows XEmacs users adopt is the alternate
keypresses for these commands.  I think they are Cut as Shift-Delete
and Paste as Shift-Insert.  I mostly use MS Windows under Wine so I'm not too sure.
But, even that doesn't work here since there is no Insert key on the MacBook Pro keyboard.

As to changing the Icon, I can't seem to find an appropriate XEmacs image file.  All of the
high-resolution XEmacs image files that I have found are rectangles.  The Icon Composer which 
OS X uses likes square files.  There must be some way to make a rectangle image file into a square, 
but this is not obvious to me at the moment.  Maybe you have a suggestion?

Thanks,

Rodney