I have uploaded videos of the solution to YouTube.
Here is a video of the first version where displays are addressed sequentially: ARDUINO DUE running 3 160x120 TFT screens - first solution - YouTube
This one shows the enhanced version where displays can be addressed at once for initialization, fill screen and other functions: ARDUINO DUE running 3 160x120 TFT screens - Enhanced Solution - YouTube
... never done a YouTube upload before, hope this works 