I would like to develop a tool for automatic kerning -- this should adjust the position of the letters in a text to correct the spacing irregularities, to ease the reading flow and to improve readability. This is also called optical kerning. To me, this is very helpful feature and I can imagine it could be of use for other open source software as well.
It may be more sensible to do the sort of low-level trickery I think you're thinking of in Pango rather than Inkscape, particularly since the criteria for ideal spacing could depend on the script the text is using (and don't get me started on kashida spacing, spawn of Iblis that it is).
Alternatively, Tav's textpath suggestion is a good one. We don't support either the method="stretch" or spacing="auto" attributes on <textpath>, both of which you could have fun with. (see http://www.w3.org/TR/SVG11/text.html#TextPathElement).
Richard.