The only explanation I can come up with for the tight gearing on the EEZZ D3 is that Dahon, after going to the trouble to engineer a pretty fly hydroformed aluminum frame for this bike, expediently used off the shelf Shimano Capreo cogs. To match the range of a common 3-speed IGH (a compromise that's worked well for 100+ years), the cassette would need to be a custom 9-12-16T.
With a rear OLD of 76mm, it's not like any other hub will fit. About the only gearing mod would be a $chlumpf geared crank.
Dahon seems to envision the EEZZ as a 'last kilometer' bike, and they've taken pains to make this intriguing platform sub-optimum to use in any expanded application.
The EEzz concept is a good one and perhaps a more ideal configuration will be available soon.
I was really hoping that the bike would work out for my needs (mainly as a multi modal touring bike, with some capability to 'cruise' at about 75 gear inches at maximum to cover the distance over uninteresting areas a bit faster if the chainring could be swapped out to a 40'ish.
I also tried its bigger brother the Qix.
Nice fold, but some refining needed in how it secures up the wheels upon the fold (it still uses the same magnet as the conventional fold Dahons)