This doesn't answer your question, but people tend to forget that bikes designed to be ridden in Holland don't always work well for other parts of the world. They have thoughtful designs for commuters because that's the way people get around in Dutch cities, but Holland is flat, so bikes do not need a lot of gears or really good brakes to be functional. And excess weight isn't that much of an issue either, which is why some Dutch style bikes (Workcycles) we see in the US are so heavy. IMO, Dutch bikes when used in places outside of and unlike Holland are a bit of a style statement. That said, there are aspects of Vanmoof that are intriguing.
I would think swapping out the rear hub for one with more gears would be easy enough, but adding the cabling necessary to operate these gears wouldn't be easy and would ruin the purist aesthetic the bike successfully strives for.