I forgot, there has been an <available> like task named <obsolete> posted to this list a while back, you should be able to pull it from the archive.
Basically this took a list of source and destination files and set a property if one of the source files was newer than one of the destination files. You could then use the if/unless attributes on targets to conditionally execute a command. This might not fully fit your requirements but could give you a start. Stefan
