Twitter Shortcode intergration

Hi, Im trying to integrate my twitter function into wordpress via a shortcode, now everything works fine except it’s not allowing me to set a number of tweets to display and is only allowing the 1 tweet to be displayed.

Here’s the twitter function im using to pull the tweets;
credit: http://blog.spookyismy.name/2010/05/18/twitter-integration-class-using-php5-and-curl/

<?php
class Twitter
{
  public $tweets = array();
  public function __construct($user, $limit = 5)
  {
    $user = str_replace(' OR ', '%20OR%20', $user);
    $feed = curl_init('http://search.twitter.com/search.atom?q=from:'. $user .'&rpp='. $limit);
    curl_setopt($feed, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($feed, CURLOPT_HEADER, 0);
    $xml = curl_exec($feed);
    curl_close($feed);
    $result = new SimpleXMLElement($xml);
    foreach($result->entry as $entry)
    {
        $tweet = new stdClass();
        $tweet->id = (string) $entry->id;
        $user = explode(' ', $entry->author->name);
        $tweet->user = (string) $user[0];
        $tweet->author = (string) substr($entry->author->name, strlen($user[0])+2, -1);
        $tweet->title = (string) $entry->title;
        $tweet->content = (string) $entry->content;
        $tweet->updated = (int) strtotime($entry->updated);
        $tweet->permalink = (string) $entry->link[0]->attributes()->href;
        $tweet->avatar = (string) $entry->link[1]->attributes()->href;
        array_push($this->tweets, $tweet);
    }
    unset($feed, $xml, $result, $tweet);
  }
  public function getTweets() { return $this->tweets; }
}
?>

Here’s the shortcode im using

<?php 

function twitter_feed($atts, $content = null) {

	extract(shortcode_atts(array(
		"user"  => '',
		"limit"  => ''
	), $atts));

	 $feed = new Twitter($user , $limit);
$tweets = $feed->getTweets();

foreach ($tweets as $tweet) {

return '<ul><li>'. $tweet->content .' by <a href="http://twitter.com/'. $tweet->user .'">'. $tweet->author .'</a></li></ul>';

 }

}
add_shortcode("twitter", "twitter_feed");

?>

Example Shortcode
[twitter user="YourTwitterUserName" limit="5"]

As I said above this code works fine apart from the tweet limit it, only ever pulls 1 tweet.

Now I’ve tried putting the code directly into the theme to see if it was a problem with the function but it works fine, so I must be doing something wrong in the shortcode. Any idea’s folks?