Login lightbox theming

I was trying to find a way of theming lightbox differently under different circumstances. I want to keep the standard style for most purposes like image galleries and then have a completely different theme for the login modal.

I had a look at the initList function and the lightbox_modal.js function so I've come up with a rather hackish solution for now.

I added a class in the modal js file to add a class modal-login to the lightbox link (obviously I'm thinking ahead here to consider adding different classes for contact form etc).

I then changed this bit of code from the initList function:

$("a[@rel^='lightmodal']:not(.lightbox-processed), area[@rel^='lightmodal']:not(.lightbox-processed)").addClass('lightbox-processed').click(function(e) {
      $('#lightbox').unbind('click');
      Lightbox.start(this, false, false, false, true);
      if (e.preventDefault) { e.preventDefault(); }
      return false;
    });

to:

$("a[@rel^='lightmodal']:not(.lightbox-processed), area[@rel^='lightmodal']:not(.lightbox-processed)").addClass('lightbox-processed').click(function(e) {
      $('#lightbox').unbind('click');
      /* Start code changes */
      var lightbox_classes = $(this).attr('class').split(' ');
      $('#lightbox').addClass(lightbox_classes[0]);
      /* End code changes */
      Lightbox.start(this, false, false, false, true);
      if (e.preventDefault) { e.preventDefault(); }
      return false;
    });

This seems to do the trick and now my lightbox has a class of modal-login and can be styled independently of other lightbox modals.

As I said, very hackish... that split on the classes is to remove lightbox-processed from the classes and I'll need to do some conditionals and just remove it from the array instead of taking the first array item (just did that to test it). This would also mean you could add more than one class and join the string again after removing lightbox-processed.

Any thoughts? Is there a better way to accomplish this, maybe through the rel on the link rather than adding classes? I'm about to head home so I'll sit tonight and try to get the code looking nicer and a little more functional then get a patch for review but comments and suggestions are very welcome.