I see nobody mentioned 3D printing yet.

This allows for almost limitless niche possibilities. For example, a climber could build a chunky Other Half with a shock absorbent video camera, extra battery and pulley system. The camera could then record their ascent, automatically climing/descending, respond to voice commands ("auto", "up", "down", "emergency" etc) whilst measuring atmospherics, GPS etc.
All easily doable with off-the-shelf components and a 3D printer.