Other coordinate issues

Allied to the thread about " SVG Path, Polyline, and Polygon data
coordinates" but, I think, distinct, are a couple of other little things
that came to mind recently in a project I am working on (to undermine
intransigence and make SVG fonts essential to all browsers that want seats
at the tables of the future - I am told hyperbole always wins arguments at
the SVG WG):

 

a.       When one has reset part of a document to have a different viewport
than another, or when one simply has changed the zoom level, it might be
quite nice to be able to do something like <elementWithCoordinateSystem
mousecoordinates="local"> so that one doesn't have to write quite so much
script to figure out where the mouse is in the new local space. 

b.      It might be nice to be able to specify units on a viewbox as percent
of the screen instead of as absolute units. One can do it through script,
but then with script who needs SVG? 

Cheers

David