Hi,
I have a shell script to create proxies with user/pass authentication. It is bit different than your requirement. For example, we can map one or more proxies to a user. And that user can use only those proxies. In usual cases, even though you implement user/pass authentication, any user can use the proxies if they know the other IP address. But my script maps proxies to that particular proxies.
By the way, i think i can make your requirement with few changes in the script.
Let me know if interested, i can provide my script for testing if required.
Thanks