You should post this in the electronics forum - C&V is all about flashlights and dynohubs and bottle generators...but since you asked, it all is way too expensive and it's all too modern looking. For $250, I'd rather buy a whole new vintage bike and wait until the sun comes up tomorrow.

If I was worried about light, I'd pop $30 for a flashlight and be done with it.

That said, If I had $850 (!) to spare, I'd get one, scavenge the innards, and stick it inside this.