Testing Pre-Production Servers Accurately?

An anonymous reader asks: "Having been granted a 90-day demo enclosure of new blade servers from a major vendor the question I find myself asking is: On a limited budget, how does one simulate 1000+ attached clients and the activity of those clients? We're a K-12 school district and our current servers don't keep up with all the roaming-profile abuse from our Windows workstations. Are there tools or tricks available to simulate load on Netware/Linux servers? The user groups around here usually answer this question with 'Get some workstations for a test lab!', there's got to be a less expensive option, right? Can we leverage our existing client populous to achieve our goal, without interrupting or changing the quality of service at the desktop, substantially?"