I know some people who have the patents on this stuff. You've only just scratched the surface...

You don't need to tell me that companies who've been doing eye tracking for years are ahead of my little homebrew project. I know that, obviously. But if I can prevent even one patent that claims "eye tracking like before, BUT IN A VR HEADSET NOW", I'll consider that a win.

You don't have a chance. Eye-tracking has been an integrated part of VR headsets for years, since the 80's, and is well and truly sealed up with patent protection. That there are no consumer-ready, plug and play products on the market today is actually a reflection of this fact, not a consequence of omission. The people with these patents are using them in industrial/medical/military/marketing applications - but the consumer version of this tech is well and truly on its way.

Once the glasses-computing wheels start to turn for consumers, expect to see integrated eye-tracking become a stock standard.