I recently found the PS1 "Silent Hill 1" shirt pocket flashlight!!!! SO STOKED!
It's a 2 port "Mophie" power bank (that just happens to be what I have.) Plug two USB plugin light modules (I'm using the Soshine smdx6 "1 watt" modules.) Have one set for high, one set for low or medium-ish. Turn them both on when you need just a little more.
Runtimes are fantastic, even 2-up on high! It's a touch of a hack to get the full 1.06-1.08 watts for each module, depending on your specific power bank. CPF has been reporting some conflicts between some banks and some modules. Typical issues concern the obliteration of modes, running medium-high only, and the power bank doing a "safety cutoff" when the module is drawing far less than a typical USB device.
I have had extreme amounts of joy walking around in a darkened house or a darkened warehouse with these babies!
I went to a motorcycle rally and "turned the modules around" so that they were shining on my shirt and not presenting bare emitters to passers by.
I got a lot of looks, smiles, and a few comments. I converted two non-flashies into straight up hungry flashaholics in training.
This setup ROCKS for safety lighting in public places where vehicles are rolling around all over the place. One in the shirt pocket, one in the back pocket. People notice you.