Reblogrewarder could be a great idea to encourage reblogging. It could work like Commentrewarder, where within a time limit of less than seven days, a percentage of the rewards are given to accounts that reblog.
However, I believe that the author of the post should be able to decide who benefits, with certain requirements. For example, with commentrewarder, the author likes the comments to select them.
Perhaps users who reblog the post should show activity on their account or reblog constantly to be valid.