I detected a problem with touch when running an app on different Android units with larger screen than 480x320px.
When running a landscape orientated app with a button/image at the right edge of the screen, touch did not respond at until I reached a bit in to the screen, pretty much same distance as screen is extended on a wider screen 45px on each side (Galaxy Tab on windows simulator).
On the left side it was no problem at all. I also have tried this on real devices with the same result. Desire HD, Galaxy S2 and Galaxy Tab 10.1.

The button is a button = display.newGroup() with an image in it.
I added printouts in eventhandler to make sure I did not miss anything but the event was not called at all when it was not responding.

In short touch outside 480px (x-axis) in landscape mode does not seem to work.

config.lua regarding screen size and scaling looks like this.

1
2
3

   width = 320,
   height = 480,
   scale = "letterbox",