I wanted to design a script for my Linux Server.
Basically all users should be denied to use socks.
However there will be a login and activate and they should be able to use the socks on the server.
I am using 3Proxy.
I can also allow this very authenticated to be done on some other server for access to another server. That is one idea.
I have also listed out few more features below..

1. There should be an authentication console for the user to log on.

2. There should be an admin console for managing the users like, enabling,
disabling or terminating a user account.

3. The user can login to the system only once at a time. If someone else try
to login using the same login details, he should be alerted or the
application should kill the existing Socks5 session.

Let me know about your price, experience and time frame reqd. to do the same.