> This works quite well, but as you'd expect the overhead is  
> ridiculous.

<xsl:number/> is designed for doing this kind of counting and many
sytems optimise its use, caching the last calculated number and not
requiring a document traversal each time.

I always avoid using generate-id for any kind of filename of ID used for
linking, the values can be highly unstable as documents are regenerated.

David