Inadvertent System Scroll Stuck - How to revert?

I believe I inadvertently intiated this condition while using my Magic Mouse A gestural slipup?? . I zoomed in somewhat and now the zoom setting seems stuck and nothing I have done will revert to the standard display setting with no zoom

Current conditions - Apple 20" wide display, resolution set to 1680 X 1050 (native) running Lion 10.7.3. The entire screen (menubar, everything) is zoomed maybe 15-20%. If I move the mouse pointer to any screen edge, the screen will scroll to show the portion of the screen not visible due to the zoom. Of course, the fonts and graphics seem pretty distorted due to the zoom not being a perfect scale of the resolution setting.

With my trackpad (yeah, I have one of those too) I can use the two finger zoom gesture to zoom in and out. When I reach the minimum zoom (where you extend beyond the "bounce" and it returns you to what should be the standard zoom, my display continues to be in this perpetual 15%-20% zoomed in state.

I have tried multiple restarts, (with and without restoring windows), safe boots, turning off zoom capabilities in the input devices and restarting, trying all kinds of resolution resets. Nothing has worked thus far

This seems to be a system software issue. I suppose eventually I may have to reinstall Lion and hope for a resolution, but I was wondering if any OS X wizards out there might have some ideas as to things a could try

Thanks

Dave