MTBR (& BLF) user GJHS is working with GearBest to try and get the Fenix BA4C bike light battery case for approximately $15. Note that this case has the cells in series and has the "opposite" end power connector from those normally used (at least with the "cheap Chinese lights"). One possible solution to the cable issue is a female-to-female adapter cable such as this one. There may be a little confusion about whether or not the unit can be disassembled easily to change out the power cord. On the one I own I could not get the contact board removed in order to do so (would have broken the contact board to do so).
So if you are interested, you can post here or over at the MTBR thread. I know there was some interest in this case about a year ago or so when Gwen was building her motorcycle helmet light.
-Garry
