Found a Minox 35 GT in super good condition (just needs a good clean). I adapted the battery compartment to use 4 LR44 cells, that are about the same size of the
Replacement Battery for MINOX 3.7v 1050mAh / 3.89Wh Camera Battery | eBay
Battery Pack for Minox
The Mighty Miniature Minox - Classic Manual Film Cameras - Photo.net