Thanks for this great post.
I do know the Daliwal et al. paper but I haven't found an answer to the following issue with these cost per ... SD comparisons:
If a study finds an impact of 0.1 SD with a cost of 10 per participant, how can you assume that a 0.2 SD impact would cost 20? Do you know of any paper that adjusts for the fact that moving from 0 to 0.1 SD is most likely (but not necessarily) less expensive than half the cost of moving from 0 to 0.2 SD?