I figured this out! For anyone with this problem in the future: there is a magnetic reed switch between the hard drive and touch pad on a ribbon cable. I cut a sliver off a flat fridge magnet and duct taped it on the reed switch. Booted up the TiBook and it was in external monitor only mode. The only downside is this disables the laptop's keyboard and touchpad.

This allows me to output 1080p from the laptop.