So I've been working on porting the animated image switching from MC wiki. There's still quite a few changes left do make before it will work for everything, including grid templates. So far I've been able to get it to work an integrate it into the item template, as you can see here: http://ftbwiki.org/Steeleaf_Armor
For the Item template, you essentially just enter the list of images, separated by semicolons as the image parameter. Do note that you can't specify a size for the images and the name shave to use spaces, rather than underscores.
EDIT: Another example: http://ftbwiki.org/Shard