Here's a video of the weird brake setup, because I think it may be easier to convey what I'm talking about through that than through typing.
https://www.youtube.com/watch?v=nntFeNlmnYs
The service manuals I have found online do not show any third line like I have on my master cylinder.
It appears that if I made/installed a reservoir closer to the 2-speed rear end controller or whatever that is in the video would serve the same purpose as the brake line coming from my master cylinder, It seems like a bad idea to be able to lose brake fluid to a leak in a different system than my brake lines.
Let me know what you think and if you have any ideas.