But anyway, if you're bound to use a parameter (I interpreted the OP's
wish in that direction), you'd still have to iterate through several
'document()' calls (correct me if I'm wrong)

Not necessarily, if you can pass in a parameter equivalent to a node set
<files>
<file>file1.xml</file>
<file>file2.xml</file>
<file>file3.xml</file>
</files>

then you can use
document($param/files/file)
and get a node set of three document nodes, one for each file.

Often you need to use a programming API rather than the command line to
pass in a node set valued parameter.

more specifically in with these two functions:
a) addParameter()		MSXML2.XSLTemplate	(Microsoft)
b) setParameter		XSLTProcessor		(Mozilla)

thanks anyway,
--
Joris Gillis (http://users.telenet.be/root-jg/me.html)
"N N1N;N.N8N5N9N1 N:N1N9 ON? N;N,N4N9 ON,N=ON1 N2N3N1N/N=N?ON= N1OO ON,N=O	"