Facebook Tab Manager 2.8.7 adds an animated preloader effect you can invoke by adding a query string parameter to the end of the URL you record in the Facebook Developers Utility. You can see the effect on the Clip File tab of the Carr Communications Inc. Facebook page.
The query string is preloader=1 as in
Otherwise, try it and tell me if it makes your page tabs feel like they load faster.
Update: the preloader effect is also displayed by default for reveal tabs created with the Reveal Tab Setup utility.