I think it will be difficult to find good research about Polyamory, since only a very small percentage of people are living the poly lifestyle. In a previous comment I estimated the frequency as something like 1/3500 in the SF Bay area and likely much lower elsewhere. Here is an interesting BBC News article about a polyamorous group.
Polyamory has a long history (under various names) as a lifestyle component of certain ideologies. Polyamory and utopian socialism have often been found together, from the early Christian Adamites, to the Radical Swedenborgians, to the counterculture hippies in the 60s/70s. These groups have tended to flame out after a certain period of time. I do think that polyamory may be sustainable for a certain niche of the population that is mentally unusual in some way (probably autism-spectrum.)
Why autism spectrum?
The idea of polyamoury is one that interests me. However, while such books as The Ethical Slut have done a good job of providing me with tools to understand and possibly handle the challenges and rewards involved, I found them unsatisfying in that they were largely based on anecdotal evidence, with a very strong selection bias. Before making the jump of attempting to live that way, one would need to know precisely the state of the art of scientific, rigourous, credible research on the topic; it is a tedious job to seek out and compile everything, but I believe it is a job worth doing.
I'll be initiating an ongoing process of data compilation, and will publish my findings on this thread as I discover and summarize them. Any help is greatly appreciated, as this promises to be long and tedious. I might especially need help extracting meaningful information from the masses of data; I am not a good statistician yet, far from it.
To Be Expanded...