Modded TomyTronic 3D stereoscopic PIC
Tomytronic is now out of business.
But the optics is really the only part of interest.
They make an optical assembly that really was 2 lenses with short focal lengths like (1 to 2 inches) and 2 mirrors, very similar to a view master.
Under the 2 mirrors can you drop your display or displays.
The cool part is on Pyrofer’s Projects he managed to get the LCD to run off a PIC micro controller. And is rendering some crude 3D. No reason this couldn't be an ARM or something with a bit more muscle.
He also managed to interface with
so it should be possible to do full VR!