Here's an initial try on that patch:

http://thpinfo.com/2010/maemo/hildon...switcher.patch

There are some problems, however (probably due to the assumption that scrolling is always vertical in other parts of the code):

• Horizontal drag motions are not always detected correctly (workaround: start drags by placing your finger just below the top edge of a thumb, and move down, then move left/right)
• The zoom in/zoom out animation is broken (zooms in too much to the right, zooms out a bit too much to the left)

Please also note that this patch applies on top of the previous patch, and that in this mode, I only allow the "single-column" (now single-row) mode, not the two-column mode. Theoretically it would be possible to do horizontal two-column (i.e. two-row) mode as well, but let's fix single column mode first.