I have recently been traveling long distances on a fairly regular basis. I have found it to be reassuring to wear a clip-on light while walking in rest areas, and a product design opportunity for a personal security product came to mind.

I have a clip-on reading light with a form factor which would be perfect for a visor-mount dash-cam, or a shirt-pocket body-cam.The best aspect is the goose-neck which would let the camera (and adjacent LED illuminator) float above the pocket, below the visor. The visual "signature" is distinctive and, with the LED turned on, quite visible (as a deterrent for potential aggressive behaviors).

Battery powered cameras are tiny, quite functional, and give decent quality images.
Better-than camera-phone-equivalent microphones are simple to implement (out on the end of the gooseneck), as is the support circuitry to connect to a large capacity flash card. All of the support circuitry should fit onto a single board, which would fit into the base directly above the three triple-A batteries in the battery pack.

Readily available, completely portable, moving easily from visor to wearable.
The ability to document nearby events without tying up a hand with a camera is good, the possible deterrent value of visibly taping a situation perhaps is better.

Another option would be to implement a wifi connection to a hotspot camera-phone, to push any recorded video directly into the cloud. Which would give this device a magnitude larger deterrence factor (I need to remember to add a large blinking red LED to indicate "Recording"). And it is useful to be able to walk after dark with a little bit of light. Not to mention it looks pretty cool.

The manufacturing process would be straightforward; it could be 3D-printed for initial production volumes, ramped up to a larger volume plastic mold once sales warrant. Probably fewer than eight or nine separate pieces going into the assembly.

Analysis of recent news events seem to indicate a market exists for this product.