I had several hacks in place in various Zend Framework based project for outputting plain text on a form and decided at long last to work from within the system again. The only solution that made sense to me was to create a Zend_Form_Element_Xhtml object that output as its value plain escaped text. Decorators can be added in the normal way to remake this control in as many forms as one might wish.

The path to the view helper for this control will need to be registered with something like the following in the bootstrap; note that I'm using "ZExt" as the library name here (as in "Zend-Extended") which is just an arbitrary name I've selected for the sake of example:

<?php
. . .
// Initialise Zend_Layout's MVC helpers
Zend_Layout::startMvc();
. . .
Zend_Layout::getMvcInstance()->getView()->addHelperPath('ZExt/View/Helper/', 'ZExt_View_Helper');
. . .

An example call to this function might look something like this:

<?php
. . .
$someForm->addElement(new ZExt_Form_Element_PlainText('someFieldName', array(
  'value'=>$someValue,
)));
. . .
// output text surrounded by table header cell tags:
$someTableForm->addElement(new ZExt_Form_Element_PlainText('someFieldName', array(
  'decorators'=>array(
    'ViewHelper',
    array('HtmlTag', array('tag' => 'th')),
  ),
  'value'=>$someValue,
)));

Aaaaaand the ZExt_Form_Element_PlainText class itself; note that this is more-or-less just a pointer to a helper as is the convention with Zend Framework's form elements. Also, thanks to a note from Ryan King (see the comments on this page), the isValid() function is overridden here to always return true; PlainText elements are always "valid", and failing validation causes issues.

<?php
/**
 * @category   ZExt
 * @package    ZExt_Form
 * @subpackage ZExt_Form_Element
 * @author     Sean P. O. MacCath-Moran
 * @email      zendcode@emanaton.com
 * @website    http://www.emanaton.com
 * @copyright  This work is licenced under a Attribution Non-commercial Share Alike Creative Commons licence
 * @license    http://creativecommons.org/licenses/by-nc-sa/3.0/us/
 *
*/
    
/** Zend_Form_Element_Xhtml */
require_once 'Zend/Form/Element/Xhtml.php';
    
/**
 * Plain text form element
 *
 * @category   ZExt
 * @package    ZExt_Form
 * @subpackage ZExt_Form_Element
 * @author     Sean P. O. MacCath-Moran
 * @email      zendcode@emanaton.com
 * @website    http://www.emanaton.com
 * @copyright  This work is licenced under a Attribution Non-commercial Share Alike Creative Commons licence
 * @license    http://creativecommons.org/licenses/by-nc-sa/3.0/us/
*/
class ZExt_Form_Element_PlainText extends Zend_Form_Element_Xhtml {
  /**
   * Default form view helper to use for rendering
   * @var string
  */
  public $helper = 'formPlainText';

  public function isValid($value){
    return true;
  }
}

Finally, the class that does all the heavy lifting (he said with just a smidgen of sarcasm) along with another bug fix from Ryan King (he said with sincere gratitude):

<?php
/**
 * @category   ZExt
 * @package    ZExt_View
 * @subpackage ZExt_View_Helper
 * @author     Sean P. O. MacCath-Moran
 * @email      zendcode@emanaton.com
 * @website    http://www.emanaton.com
 * @copyright  This work is licenced under a Attribution Non-commercial Share Alike Creative Commons licence
 * @license    http://creativecommons.org/licenses/by-nc-sa/3.0/us/
 *
*/
    
/**
 * Abstract class for extension
 */
require_once 'Zend/View/Helper/FormElement.php';
    
/**
 * Helper to generate a "plaintext" element
 *
 * @category   ZExt
 * @package    ZExt_View
 * @subpackage ZExt_View_Helper
 * @author     Sean P. O. MacCath-Moran
 * @email      zendcode@emanaton.com
 * @website    http://www.emanaton.com
 * @copyright  This work is licenced under a Attribution Non-commercial Share Alike Creative Commons licence
 * @license    http://creativecommons.org/licenses/by-nc-sa/3.0/us/
*/
class ZExt_View_Helper_FormPlainText extends Zend_View_Helper_FormElement {
  /**
   * Generates text.
   *
   * @access public
   *
   * @param string|array $name If a string, is set as the "value" and rendered. The
   * real "value" setting will take precidence if set. In effect, the "name" value
   * become the default for "value" when "value" is not set. If an array, all other
   * parameters are ignored, and the array elements are extracted in place of added
   * parameters.
   *
   * @param mixed $value The element value.
   *
   * @param array $attribs Attributes for the element tag.
   *
   * @return string The element XHTML.
  */
  public function formPlainText($name, $value = null, $attribs = null) {
    $info = $this->_getInfo($name, $value, $attribs);
    extract($info); // name, value, attribs, options, listsep, disable
    if (null === $value) {$value = $name;}
    
    return $this->view->escape($value);
  }
}