something akin to the CAD feature request is the possible use of the svg coordinate system features, as described
http://www.w3.org/TR/SVG/coords.html i think it's quite possible in svg to set up objects and viewports so that what for a local object is up is in fact down (or left or other) higher in the hierarchy.
i think the other kind of requirement to temporarily rotate view for doing artwork (especially with tablet workflows) is quite different, i.e. only temporary and should not affect the underlying svg. having a tablet i appreciate the need for this feature request, as the much more natural input using a stylus is easier when doing vertical oriented strokes, just as a pen & paper drawing would be physically rotated when doing non-digital art/graphics work. which is also why a lot of the higher end art graphics programs have key shortcuts to quickly and temporarily rotate the whole view.
something entirely different is the facility of some graphics cards to rotate entire screen (including OS and all apps) with keyboard shortcuts. but this doesn't work/help as the input device (tablet) won't match screen orientation.
not sure if i covered all the angles, but that's fairly complex by now.