While I was digging around looking for similar setups, I came across PixelCamera2D. The approach is somewhat similar, though it is already packaged as a prefab.
Regarding the fixed resolution, I tried out Packer's Auto Resolution script and it works great. I just made a few tweaks. In the Update method, I also call the AutoScreenSize if Screen.width != Screen.height, and I have an IsPowerOfTwo method instead of checking for each height value. You can take a look at the code here. The code ensures pixel perfection; it changes the resolution to the next power of 2 smaller than the chosen resolution. It works for both windowed and fullscreen modes.