Hello,
I have been programming bots for some time now. Although its not my main area in Elance, I just came across your project post by luck and though since you are offering some good moeny for the job, I should give it a try.
I make bots that use proxies and automate different tasks.
I have made bots that create yahoo accounts, hotmail accounts, do social book marking or even submit articles to different directories.
I can give you a demo of website traffic simulator bot that you are talking about, and customize it whatever way.
Please PM me to request a demo and I will send you bot as soon as possible.
Again, its not my main business on elance but I am very expert in it.
Best
Bobby