"...HTMLArea will give them too much power to potentially screw up the page..."

And yes, HTMLArea really only works well on Windows boxes, but 99% of the users "out there" have Windows. The latest versions of Firebird and Mozilla will render HTMLArea V3.0, but i have had intermittent results with those browsers on Linux boxes - some work and some don't. But remember that you don't have to run IIS or anything like that to get HTMLArea to work. It is a client side technology, and surely your user has a Windows box available. (I actually had a client that only used Macs, and thus i had to provide a file upload alternative).

As for the last question ... i would rather read in the file, display it for the user somehow, and then write the entire file back out instead of using in-place editting. Having to fork and exec another shell to the Perl interpreter should be avoided when it can.

Best of luck to you! :)

UPDATE:
Here is a quicky script that might help you out. As long as you can set the permissions for the store file (i named it CONTENT with no extension for no real reason) you should be good to go. I used CGI.pm, mainly because it is readily available and it handles HTML entity escaping for you.

#!/usr/bin/perl -T

use strict;
use warnings;
use CGI qw(:standard);

print header,start_html('mini cms');

if (param('content')) {
   open FILE,'>','CONTENT' or error("Can't write content file: $!");
   print FILE param('content');
   close FILE;
}

open FILE,'<','CONTENT' or error("Can't read content file: $!");
my $content = do{local $/; <FILE>};
close FILE;

print start_form,
   textarea(content => $content, 10,50),br,
   submit,
   end_form,
   div({id=>'content'},$content),
;

sub error {
   print pre(shift),end_html;
   exit;
}
[download]

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)