<p>How can I represent the following in XSD.</p>

<pre><code>&lt;price-update&gt;
    &lt;![CDATA[
      arbitrary data goes here
    ]]&gt;
&lt;/price-update&gt;
</code></pre>

A CDATA tag is merely a means of escaping data as a text node.  Therefore you cannot stipulate that you require a CDATA node.
From a DOM perspective, the following documents are identical:
```
```
<doc>value</doc>
```
```
and
```
```
<doc><![CDATA[value]]></doc>
```
```