> 1) I'm still "cheating" somehow, by using saxon:evaluate. If 
> I wanted to do without, which way would I have to go, 
> roughly? (Is this related to Joe's comment "if the full 
> XPaths are stored in the config file then some extension is 
> needed to evaluate these dynamically"?)

If you've got XPath expressions stored in an XML document, then the only way
to evaluate them with standard XSLT is to generate a stylesheet and then
execute it. 

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