That's exactly what we were doing (without an FPGA), you need at least 8 sensors to properly localize attention though (based on our experiments). Things like the Muse I highly doubt work effectively
Perhaps you should try it instead of "doubting" without any basis. Based on my experience Muse is a great product and it delivers exactly what it says. It's hard to see any other EEG product competing with it any time soon (assuming similar cost usage style. Of course something like what "40 years of zen" are doing will be much more powerful).
Did your experiment show a measurable signal difference between stable vs wandering attention? Mindfulness supposedly helps with executive dysfunction (either due to frontal lobe brain injury or ADHD). It would be an interesting experiment to see if feedback via such a headband can help improve focus.
Coming from the RF world, those numbers honestly seem trivial for processing. Is it just a money issue or is nobody willing to build something like you did?
Muse Headband did, and they have a finished working retail product which reliably improves meditation practice. I've tried it personally. (No affiliation.)