Ok so I was looking at my Ipod video 30gb that I have running an open source firmware called Rockbox and I noticed that in the Rockbox firmware there is an option for USB HID such as Mouse,Multimedia,Browser, and Presentation. so you can use the Ipod as a mouse or one of the other 3 options.
Now for the Question...
Do you think it might be possible to code a new USB Hid device such as a programmable keyboard into rockbox? So it would then be like an ipod version of the USB Rubber Ducky? Say you code the keyboard HID "plugin" to read the keyboard commands from say a text file (.txt) and then run it buy pressing the play button or having it run automatically. Maybe have multiple HID devices for different payloads. Also with the Rockbox firmware with USB HID turned on you still have access to the ipod hard drive,so you really don't have to worry about messing with sd or micro sd cards.
Well sorry for the semi long post,Just putting my ideas out there :)