I dunno about coding. I note we already have VP for ordinary votes, and all this would require is setting VP decay to 100% with no recharge for witness votes.
Seems pretty easy, mayhap.
I appreciate your forwarding this idea to the community. We do need to do something, and even 1 Steem = 1 vote probably isn't nominal to secure governance from the Sybil attack that has captured it. It would make it harder, and that's good. So would limiting the number of witnesses each account could vote for, since it reduces the stake multiple account holders could throw at a vote.
Maybe together both mechanisms could combine their improved security impact beneficially.