I have just file released plplot-5.0.4-3mdk.i686.rpm and plplot-5.0.4-3mdk.src.rpm
at
http://sourceforge.net/project/showfiles.php?group_id=2915&release_id=39317. These rpm's are only suitable for Mandrake 8.0, but the source rpm should be easy to modify for other distributions.