I'd like to be able to hold hold the left mouse button down for about 5 seconds and have it act as the right mouse button. Is this possible?

You might possibly be able to do some form of customisation with X itself here - although you will no longer be able to drag and drop items. I'm not sure if this is possible though.

Simpleblue,

Can you explain (please) why you want to avoid using the traditional QT::RIGHTBUTTON for context menu?

Qt::LeftButton isn't tied only to drag-and-drop, it's the button for gestures. And BTW, (IIRC) The context menu pop-up doesn't occur on a click -- it's almost unique, happening immediately after the 'Press' of Qt::ButtonRight. (Even if you hold it down.)

Are you somehow stuck with a less-than-two-buttons "mouse device"?

Please advise, as I intend to enable "mouse shortcuts" within Qt 5.1 -- and I had not considered bothering with 'press and hold' Actions.