An update to the "Rotating Tweets" Wordpress plugin. Instead of taking a single twitter screen name, now I space-delimit as many as I wish. Then I loop around them. Finally I sort them by date via the usort function and its related callback.

gistfile1.php

$screen_names = explode(' ',$tw_screen_name);
      $twitterjsons = array();
		foreach($screen_names as $screen_name) {
			$apioptions = array('screen_name'=>$screen_name,'include_entities'=>1,'count'=>10,'include_rts'=>$tw_include_rts,'exclude_replies'=>$tw_exclude_replies);
			if($tw_search) {
				$apioptions['q']=$tw_search;
				$twitterdata = rotatingtweets_call_twitter_API('search/tweets',$apioptions);
			} elseif($tw_get_favorites) {
				$twitterdata = rotatingtweets_call_twitter_API('favorites/list',$apioptions);
			} elseif($tw_list) {
				unset($apioptions['screen_name']);
				$apioptions['slug']=$tw_list;
				$apioptions['owner_screen_name']=$tw_screen_name;
				$twitterdata = rotatingtweets_call_twitter_API('lists/statuses',$apioptions);
			} else {
				$twitterdata = rotatingtweets_call_twitter_API('statuses/user_timeline',$apioptions);
			}
			if(!is_wp_error($twitterdata)):
				$twitterjson = json_decode($twitterdata['body'],TRUE);
				if(WP_DEBUG):
					echo "<!-- Rotating Tweets - got new data -->";
				endif;
			else:
				set_transient('rotatingtweets_wp_error',$twitterdata->get_error_messages(), 120);
			endif;
			$twitterjsons = array_merge($twitterjsons,$twitterjson);
		}
		usort($twitterjsons,'tweet_sort');
		$twitterjson = $twitterjsons;


function tweet_sort($a,$b)
{
  $a_date = strtotime($a['created_at']);
  $b_date = strtotime($b['created_at']);
  return ($a_date < $b_date);
} 

Many thanks for this. Love the interface improvement so I've copied it. I've gone with an approach that uses the Twitter Search API to handle multiple accounts.

if(empty($tw_search)):
    $possibledividers = array(' ',';',',');
    $rt_namesarray = false;
    foreach($possibledividers as $possibledivider):
        if(strpos($tw_screen_name,$possibledivider) !== false ):
            $rt_namesarray = explode(' ',$tw_screen_name);
            $tw_search = 'from:'.implode(' OR from:',$rt_namesarray);
        endif;
    endforeach; 
else:
    $tw_search = trim($tw_search);
endif;