first of all, thanks @iKirin for posting the specs!
same as the post above, I too am looking to power the V through usb-pd enabled powerbanks, it would be nice to know the power rules (though i vaguely remember that info being posted somewhere else, max is 27W@9v/3A).
@hellBENder you might want to check out the Anker 28600mAh, since it seems to be able to input & output at 9v/3A
click to show pic
one thing I notice, however, is the lack of an additional USB charging port on the charger as to let it charge more than one device at a time (like Aukey PA-Y10). Maybe nobody wanted this feature when deciding on the V’s charger, though I find it quite useful. Good job on the modular connectors, wish the aukey charger has them too.
edited a few times to add details i thought of after posting, better than making a few posts IMO