MSSQL 2000 Replication & Clustering Example Sites

Can anyone give me some examples of companies using MSSQL 2000 replication and/or clustering with high transaction volumes? I've only been able to find two case studies published by Microsoft, one for Countrywide and one for Wildcard Systems. Countrywide I've heard of, Wildcard I have not and neither case study gives me a hint of transactions per hour or day being synchronized.

Basically, I'm fighting a battle with some of my coworkers to use MS's built in replication and clustering services or write our own because MS's advanced services have yet to be proven in high-volume (50,000+ updates per hour) real-time sites in the eyes of some of my coworkers.

Any info would be GREATLY appreciated!!!