I still enjoy my Tool AA mod with rechargeable Nitecore 14500 every day.

I don’t know why there is no such light on the market, but I would buy something similar if a BLF project would emerge.
I almost lost it a couple of times. Would be great to have one off the shelf to replace it.

Only thing I might change nowadays is switch to another LED. XP-L2 U6 90 cri for instance or Luxeon. And it would be perfect if it could accept regular AA’s as a backup.