Fiddling about with creating a bukkit plugin to replace Clocksign, got it reading and interpreting the sign correctly, now just got to work out the methodology for getting an individual Lever reference from a block object (think I'm nearly there) so that I can make them switch via an alternate looped thread. Seems pretty simple at first, but Blocks don't know, as such, that they are levers, it's a property of a value that is stored inside to Class, it's now just a question of which value to I need to pull and convert to a Lever.
Much Bukkit Javadoc browsing will ensue, I suspect.
