Devil's advocate here -- Looks to me like this is nothing more than 4x 1800mah nimh aa batteries in a nice case.
Why not just buy high capacity aa sized nimh batteries (1800 mah to 2500 mah) are available and run them internally in your d100 and sbm-1. With the d100, if you just change batteries with tapes, you'd NEVER have a problem (and with high capacity nimh batteries, you'd likely have no problem running a pair for the entire nite), with the sbm-1, one set of batteries should last at least as long as the external powerbank -- worst case, change batteries when you change on the d100 and you're fine. This way, no cords/adaptors/etc., bag can't get much slimmer.