Hey,

i used a basic wooden frame and a 24 inch monitor.

Monitor
i used this monitor, because its very flat and had the perfect size for the 60x40cm glass:
https://www.amazon.de/gp/product/B01AJTVCA8

i did not remove any plastic from the monitor, so i can reuse the monitor if i want.

Glass
http://www.glas-per-klick.de/spiegel-antikspiegel/spionspiegel.html
(german website)

it has 3% opacity. For me it was important, that you can’t see the monitor that well (gray background light), so this one was a perfect choice. Maybe in an open room with sunlight you need more opacity.

What i may do
Silicon gap between mirror and wooden frame
Add motion sensor for energy saving purpose
Build some modules for smart home

Screenshots

Ready mirror

Back of the mirror

For the front border i just used a wooden strip from my local shop