Now to the matter.
I haven't got a clear idea what to do, I'm not even sure about the guidelines for this task nor have a complete feeling of the goal. On the other hand I have some chances to make a piece of valuable work here.
The task was described as "likely XSLT". Fortunately I have the basic understanding of XML and XSLT (I've recently accomplished a subject at my university devoted to XML and XSLT, so I'm quite fresh with it). In addition, I got to like it and feel a need to deal more with such translations.
The fact is, I don't know the "XML Schemas" and practical aspects of SVG and KML. I will need some time to get through their documentations. Anyway, both specifications are worth knowing, so I will gladly learn them.
I guess the job may be considered as import and export respectively. Importing (KML to SVG) shall be relatively simple and with a small risk of an "out-of-time" defeat. The other direction (export) seems more hard and needing deeper considerations. Of course, the importing part might also need some "parameters" (options in import wizard?).
As I am freaky/scarry of not meeting the deadline, I like to find a safe-feeling solution first. An example of such is making a little website for converting KML to SVG using for example Firefox built-in XSL processor (I've used this solution in my last XSLT project, although it didn't involve any SVG rendering). I have then made a silly and tiny web framework (using PHP + .htaccess + mod_rewrite) for passing parameters to the XSLT file (parameters are dynamically inserted into original file as lines with an xsl:param definition each). Thus I could make a small portal driven only by XSLT :-) As this solution is quite comfortable and "recent" for me, I believe "I can make it", and in the meantime we can optionally consider if I will be able to deal with Inkscape internals (that is what I don't know at all, so this may be more risky).
That's it for a minimum. I'm waiting for your opinion and expectations. If you agree for solving this task via XSLT, I'm likely to success with it.
Piotrekk