Recently someone suggested a really simple solution for this. Frontends have to do some work to better navigate the users to take advantage of this possibility. It's all very simple - when a post's payout has already been paid, you don't vote on the post, you instead make a comment and set the post author as your comment's payout beneficiary. Then you upvote your comment. This will have the same effect as you voting on the author's post. Plus it will leave a comment on their post, even better.

Does this meet your requirements?