Just committed an initial implementation of xsl:call-template. It does the right thing for correct XSLT. At the moment, though, it can do the wrong thing for incorrect XSLT - if you give an unknown name it raises a run-time error not a compile-time error.
Things are actually getting quite useful now. If you'd like to have a play, grab the mangle branch from Subversion
svn co svn://jezuk.dnsalias.net/jezuk/arabica/branches/mangleand have a look in
include/XSLTfor the bulk of the code and in
examples/XSLTdirectories for a little sample command line XSLT transformer to play with. Comments, bugs reports, patches are all very welcome.