Does anybody here know of recent research with real internet traffic which compares different sample rates wrt the representativeness of the resulting flow data?

You might take a look at: Nick Duffield, Carsten Lund, Mikkel Thorup. Charging from Sampled Network Usage. ACM SIGCOMM Internet Measurement Workshop, November 2001. http://www.icir.org/vern/imw-2001/imw2001-papers/03.pdf It may be along the lines your thinking about. allman --- Mark Allman -- BBN/NASA GRC -- http://roland.grc.nasa.gov/~mallman/