Would anyone have any direction on what kind of projectors North was using for this product? I have no idea where to start searching.

In the same way, I would also be very interested in any further info on Ellsworth's Tilt Five projectors, bottom right-right of [1] (full text of interview [2]). Interesting video with info on the (retroreflective) optics system here [3].

[1] https://web.archive.org/web/20200722042213im_/https://i0.wp.... presumably shows three generations of the product. From left to right board, camera and projector.

[2] https://skarredghost.com/2019/09/24/interview-jeri-ellsworth...

[3] https://www.youtube.com/watch?v=AB4NjMWKV0s