Technically, what you want to occur is a keystroke event plus a movement event on the tablet. This is only possible at the application's code level which is something Adobe would have to do.
That said, here is an alternate option. Not exactly what you want to do, but an option.
- Set the front button of the pen (the portion of the button nearest the pen tip) to Z.
- Tap + dragging over a portion of the document that you wish to zoom into.
- Holding Alt while performing step 2, zooms out.
Essentially what you are doing is selecting the Magnifying glass from the front button of the pen. Its not elegant, but it is an option.
Note: InDesign supports “spring-loaded keys”, meaning temporary selection of a tool. Holding (not tapping) any key associated with a tool, using that tool to perform its function, then releasing the key returns you to the previously selected tool. This feature was introduced in CS6 I believe. Photoshop shares the same spring-loaded functions.
After further thought, another consideration--one that I think might be more effective--is setting the front button to the Hand tool (H). This can be useful for zooming in and out and scrolling through a document. This is accomplished by using a feature in InDesign called “power zoom”.
- Set the front button of the pen (the portion of the button nearest the pen tip) to H.
- While golding the front button down, press your pen to the tablet. The document zooms out so that you can see more of the spread. A red box indicates the view area.
- With the the front button still pressed, and your pen still touching the tablet, drag the red box to scroll through the document pages. Tip: Pressing the arrow keys on the keyboard will change the size of the red box.
- Release the front button and pull your pen away from the tablet to zoom in on the new area of the document. The document window returns to its original zoom percentage or to the size of the red box.