FWIW, Schlumpf Cranksets have a Planetary gear in them to create a second ratio, with out a front derailleur

His Speed Drive is 1.6X in overdrive mode,
there are 2 - 2.5X cranks .. 1, overdrive 'high speed drive'
and reduction gear 'Mountain Drive'

I got the latter for my Brompton, with an AW3 hub .. 15t cog on the hub in a 349 sized wheel

so, in low range, I have 3 more gear ratios.

oh, and you can reduce the width of many IGhubs , just take off some added Nuts on the left end of the axle, My Folding bike has a 117 wide over lock nut distance..

So not prying the dropouts out to fit a 135 hub can me avoided.

Folks have used a Sachs (SRAM?) Duomatic, a kick back shift 2 speed hub, and a Schlumpf crank to have 4 ratios,
and still no shifting cables.

some current SRAM IG hubs use a shifting 'klickbox' at the hub which is a continuous cable in housing all the way from the handlebar control , no fittings needed , just zip-tie the housing to the frame.