The MERIT folks had some records of real BGP traffic of millions of packets, and could play them back. You might poke around www.merit.edu. On Fri, 17 November 2000, "Timothy Brown" wrote:

Does anyone have a script or a series thereof to do large-scale BGP testing? I'm looking for scripts that will generate and nail down several hundred networks of varying sizes, and/or fake peering relationships with a similar purpose, and/or do things that don't meet the BGP protocol standards, etc.