> If you are only needing it to work on the given document then 
> I think in
> general for two element nodes, the shortest relative Xpath 
> can always be
> expressed in the form
> 
> xxx::*[n]
> 

Do you want the shortest XPath expression, or the XPath expression whose
evaluation touches fewest nodes?

   following-sibling::*[5]/child::*[2]

or

   following::*[29]

?

Michael Kay
http://www.saxonica.com/