Well the system must store my votes to stop me from voting twice. So all I was asking was whether it was possible to make that voting history available to the me.
You pretty much answered that question to yourself. Yes, the system stores each vote for a node, which involves the storage of IDs of the monks that voted for it. I guess there isn't an index on that, so gathering a monk's voting history would put some load on the database; and creating an index wouldn't improve neither performance nor storage of PerlMonks, either.
If we were to create such a think, to what end would that be? Tell a use case.