The items below are jumbo-sized when held.

• All turtles.
• Pocket Computers.
• Floppy Disks
• Printed Page
• Printed Pages
• Printed Book
• All modems
• Networking Cable

Picture for reference http://i.imgur.com/mf4RfBW.png

( 1.9.4, Forge 12.17.0.1976, Java 1.8.0_65 64bit, no other mods loaded)

Duplicate of #112

this is also the case for the item entity version of these items

Fixed in pr1