Im looking for a simple bit of code that will let me add the following html into my zend form:
        
You have to add decorator.
Any markup decorator may be helpful.
For further information about decorators see: http://www.slideshare.net/weierophinney/leveraging-zendform-decorators
How about using some JQuery:
Something like:
<script language="javascript">
    $(document).ready(function() {
        $('#submit-element').append('<div id="wmd-button-bar" class="wmd-panel"></div>');
    });
</script>
You can create your own view helper libraray--App>View>Helper>PlainTextElemet.php
Create a folder in your library folder that name is App so a folder that name is View so in View create Helper Folder so in Helper folder create a class with PlainTextElement name same following
 class App_View_Helper_PlainTextElement extends Zend_View_Helper_FormElement {
        public function PlainTextElement($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 $value;
          }
    }
Then in libray same above create a class App>Form>Element>PlainText.php
And put folowing code in this class
class App_Form_Element_PlainText extends Zend_Form_Element_Xhtml {
    public $helper='PlainTextElement';
    public function isValid($value){
        return true;
    }
}
Now in your form you can create each html code you like:
$someValue = '<div id="wmd-button-bar" class="wmd-panel"></div>';
        $this->addElement(new App_Form_Element_PlainText('pliantext1', array(
                            'value'=>$someValue,
        )));
Don't forget in your application.ini add fllowing lines too:
 autoloaderNamespaces.app = "App_"
 resources.view.helperPath.App_View_Helper="App/View/Helper"
You can try this way, no config, just one extension class reference: http://www.zfsnippets.com/snippets/view/id/50
<?php
/**
 * Form note element
 *
 * @author Ruslan Zavackiy <ruslan.zavackiy@gmail.com>
 * @package elements
 */
/**
 * Loads helper Zend_View_Helper_FormNote
 */
class Custom_Form_Element_Note extends Zend_Form_Element_Xhtml
{
    public $helper = 'formNote';
}
?>
then
$companies->addElement('note', 'companyNote', array(
            'value' => '<a href="javascript:;" id="addCompany">Add Company</a>'
        ));
This functionality is built into Zend via Zend_Form_Element_Note.
new Zend_Form_Element_Note('forgot_password', array(
    'value' => '<a href="' . $this->getView()->serverUrl($this->getView()->url(array('action' => 'forgot-password'))) . '">Forgot Password?</a>',
))
Create a custom Decorator that return the label(or anything else):
class My_Decorator_CustomHtml extends Zend_Form_Decorator_Abstract {
            public function render($content)
        {
            $element = $this->getElement();
            if (!$element instanceof Zend_Form_Element) {
                return $content;
            }
            if (null === $element->getView()) {
                return $content;
            }
            $html = $element->getLabel();
            return $html;
       }
}
Place this in the decorator path
<pre>$form->addElementPrefixPath('My_Decorator',
                            'My/Decorator/',
                            'decorator');</pre>
Create the element and put the custom html in the label
$html = '<div id="wmd-button-bar" class="wmd-panel">some text....</div>';
 $element = new Zend_Form_Element_Hidden('hidden-input', array(
                                'label'=>$html, 
 ));
$element->setDecorators(array('CustomHtml'));
//add it to the form
$form->addElement($element);
and that's it