Line over the cursor using the resource pack Ovos Rustic Redemption and holding an item. Its latest download (v1.1.5 for 1.8.x) contains no animation in it. The line can only be seen when an item is in the hotbar. The link to the resource pack can be found here

http://www.minecraftforum.net/topic/901498-x6417x-18-snapshots-ovos-rustic-pack-redemption-v115-updated-2014-05-12/

Other resource packs now have either a box or a blurred cursor in the middle when they did not previously. I did not find anything that changed how the cursor is rendered on the change log.