You're right, I can't find any evidence other than several polyphasic sleepers' blogs. I can find a handful of articles on polyphasic sleep, but all of them are behind pay-walls and I can't get to any actual data.

The only actual data I could find related to sleep periods evening out to a similar daily distribution after 45 days.

I could probobly help you access the journals if you want to investigate further, I'd be interested in hearing the answer.

At this point, I don't think there is much in the way of real work behind it. From what I can tell there has been one paper written about it (http://www.informaworld.com/smpp/ftinterface?content=a782431...), which is a "field study", not a laboratory test.

All I seem to find are pseudo-science and anecdotes supporting both sides of the argument, with no actual evidence.