I love your project, and I'm trying to build a reputation on this site, so I'm willing to lowball the price quite a bit. It's a win-win!
Your project, though very specific in some areas, is more vague in others, so I'm making a few assumptions:
1. I'm assuming you're looking for something that you can run on the spot, without much configurations, overhead, and installation. Otherwise you could just install and configure proxy software like squid3.
2. You want it to be portable and simple/quick to use, specially if you want to run it on hourly servers.
3. Lastly, I'm guessing you're going to use it to either connect to, or connect from, a secure connection with a username/password, though I'm guessing it's more likely the latter.
This should probably be built as a socketed connection (probably encrypted through SSL if security is an issue), with an subscription verification upon connection (aka user/pass if you want to provide it as a service), and in either PHP or C++, depending on the intended usage and desired setup.
Again, I'm making a few assumptions based on your description, but that seems like a good project. Time frame for delivery and cost can change depending on the specifics, but my bid feels like a fair baseline to work from.
I'd love to talk to you about this project even if you end up going with a different developer. I'm quickly reaching char limit in this bid description, and there's a whole lot more details to maul over.
Joel Villasuso
Computer Engineer