I saw those Mecarmy Pt series lights a couple of weeks ago on Massdrop.
The Mecarmy Pt’s have charger built in, supplied with a li-ion cell, are produced in four size formats, based on the cell.
Right now they are priced out of the range your looking at, but Massdrop may have them return in time for the holidays.
There are some reviews PT-16
PT-18