I DO NOT like the idea of someone else having control of a system run on my site that must apply for any and every game hosted there.
Welcome to the world of software licensing. igLoader is written in c++. The actual operation of the dll is quite simple, in terms of what it does, it's the implementation that's the killer.
I'd offer a custom build but the issue for you is that I would still need to lock it down. I can't risk the reputation of my software or company due to someone using it to deliver some software nasties. I'd rather lose the orders than take that risk. Security should be the primary concern.
You could use Grasshopper, it's free but not open source, it works but it's not as flexible, I'm not sure if it can pull remote files yet and I don't think you can brand it.