After I painstakingly re-calibrated my monitor and with an enhanced shader that provides HDR I've found nights can be PITCH dark now. Alteration light spells and Torches help, but that can also really hurt my Sneak chances, as I play a Sneaky character. Instead of using only Detect Life I'd like to be able to use Night Vision as spell effect and a potion effect.

There are already mods out there that make things darker (like Skyrim Enhanced Shaders) and you'll find some areas really need something like Night Vision to make your way around.

It's also for werewolves

Werewolves get Detect Life, not Night Vision.

Can't you just add the khajiit night-eye power with the console
player.addspell aa01d