Having seen pinstadiums installed in a ST:TNG at an arcade I was impressed with how well they lit the playfield allowing for the ball to be tracked much easier. It's no surprise that it is one of the most played machines there.
The 4 major downsides were:
1) The price at anywhere between $260 and $400,
2) The fact that they had to be installed inside the machine, thus making moving them from machine to machine a pain,
3) That to lift the playfield you had to remove them, and
4) The 'rainbow stripes' they cast on the metal ramps.
So I set about trying to build something that would
1) Do the job of lighting the playfield evenly to assist in streaming, as well as helping track the ball,
2) Be easily moved from machine to machine, without the need to access inside the machine, and
3) Be lightweight and portable so they could be used in an arcade, bar or competition where the lighting isn't perfect, thus replacing people using a LED headlamp.
After a month, and numerous failed attempts I'm pretty happy with what I've produced.
They are magnetic and attach to the siderails/glass guide. The battery pack is also magnetic and attaches to the back box hinges. They are finished in black 3D carbon wrap, and are almost unnoticeable while on the machine.
You can read more about them here
https://www.pinballinfo.com/community/threads/portable-pinstadium-alternative.44412/