How to find the leading researchers in a new field

Problem is that you hamstrung yourself by eliminating the only correct strategy: doing a long literature survey yourself. You wish to rely on proxies, and sometimes surveys can do that for you, but other people's opinions of "good" and "bad" are just that: opinions.

The only way to really get a sense of good and bad is to read a LOT, think a lot about what you read, discuss with people who might know more about the area, think a lot more, read more, and repeat.

Well, one slightly unorthodox method for finding these might be to find the "society" representing the field, and find who their recent award winners are—particularly if they have "young investigator" awards that will recognize work considered to be of significant impact.

The relative advantage of this approach is that it it represents the consensus of people working in a given field; the disadvantage is that the consensus may be of only a handful of members on a committee. But these are people who in principle should know the ins and outs of their field better than most.

My personal technique is to read the introduction to a number of research papers and find the most commonly cited papers/authors/author groupings. This will tell you who is the most "influential", i.e. whose work is driving the field and causing others to perform research branching of their original findings. This is similar to examining publication count, but more useful in that you can see how broadly the citations are applied, and judge from context whether the citation has merit.