Here is a wacky idea, now I've done something like this in the past (long ago) so don't got any sources, but the gist of it goes like this:
1. Code a program that adds certain rule (keeps it updated if needed) to the
hosts file. This serves to redirect the traffic wanting to access the launcher webpage to our own program.
2. Code the program to accept http requests over the local IP only and a specific port.
3. When you run the launcher (official one, nothing changed) it will read the data served by your own application, thus you can modify the output and show what ever you like on the launcher.
A lot of work but the payoff is not tampering with the game files at all, only the start page shown on the launcher. You can add all the options and such as html forms and have the program read the post or get requests made by the browser/launcher and store that information somewhere locally.
Just an idea.
