You can use SteemPeak.com (Best front-end ever!) and make a comment on a previous post and set the beneficiary for the comment 100% to the author you want to reward ;)
Neat work around to support an author whos recent posts have all paid out.
It has to be a comment to the parent post though; for example the comment I am making right now I am unable to set a beneficiary for... but the first comment you made here you would have been able to if using SteemPeak.com ;)