You know, this is something that's needed doing for quite a while. I wonder, once the design is 'completed' (are they ever REALLY complete), would you be interested in working out a deal to put your system into production? Maybe something along the lines of royalty / licensing payments going to a school club or science department, or something of that nature? Since it's your own complete design, and I'm assuming your own code, there wouldn't be any outside licencing issues to worry about.
I'm not sure what I would license. Most of the hardware is either open source(Arduino) or just basic circuits(MOSFET driver boards). Even the switch board is just a series of shift registers. I'm adding in some OPP hardware now. For the code, it's just Arduino code on the controller side and MPF Python on the other side. I couldn't copyright my changes to MPF even if I were inclined to do so.
And I didn't redesign the playfields(even my more in-depth Flash retheme is just getting a new magnet under the hood). If I ever build a completely custom playfield, I will revisit the question.