Possible to defer loading of jQuery?

Try this, which is something I edited a while ago from the jQuerify bookmarklet. I use it frequently to load jQuery and execute stuff after it’s loaded. You can of course replace the url there with your own url to your customized jquery.

(function() {
      function getScript(url,success){
        var script=document.createElement('script');
        script.src=url;
        var head=document.getElementsByTagName('head')[0],
            done=false;
        script.onload=script.onreadystatechange = function(){
          if ( !done && (!this.readyState || this.readyState == 'loaded' || this.readyState == 'complete') ) {
            done=true;
            success();
            script.onload = script.onreadystatechange = null;
            head.removeChild(script);
          }
        };
        head.appendChild(script);
      }
        getScript('http://ajax.googleapis.com/ajax/libs/jquery/1.5.2/jquery.min.js',function(){
            // YOUR CODE GOES HERE AND IS EXECUTED AFTER JQUERY LOADS
        });
    })();

I would really combine jQuery and jQuery-UI into one file and use a url to it. If you REALLY wanted to load them separately, just chain the getScripts:

getScript('http://myurltojquery.js',function(){
        getScript('http://myurltojqueryUI.js',function(){
              //your tab code here
        })
});