We are building a mobile app where we need to support user concurrency of maybe 10000 initially. The server is completely WCF based and we need to do performance and load testing against these services. VS2012 has web and performance tests but this is not sufficient for our scenario. VS2012 can only send the exact same request concurrently. We need to send different concurrent requests, maybe change the username, or preferences, etc in each request. Would appreciate it if anyone could help me out, really need this urgently.