Rather than paying the curation rewards to the author, the auctioned rewards could be distributed to later voters.
Not sure if you got this idea from me in chat or if great minds just think alike, but under the current curation rewards algorithm, it won't work. Its vulnerable to sybil. A front running bot can just use one account with half his power to vote early in the auction and one exactly at the 30 minute mark, that will dominate the reverse auction pay-it-forward.