WAPT

From SoftLogica:

WAPT is a load and stress-testing tool for websites and web-based applications. It uses a fully customizable set of virtual users to simulate a real-life load. Test scenario can be detailed up to unique parameters for each individual user. Testing of dynamic web applications, recording and playback of HTTPS requests, and several authentication schemes are supported. Descriptive graphs and reports allow you to see and fix performance bottlenecks. Version 4 features: multiple virtual user profiles; support of IP spoofing; real-time reporting; support of different language encodings; command-line interface; support of persistent cookies; test scenario and profiles in XML; test run summary reports.