drop bars ?. eliminates any hydraulic brake options, all are for 22.2 bar, 7/8"
road bars are bigger.. 23.8, 15/16"

I run Campag Road levers, their older pre brifter type, on Nitto 'Mustache' bars,
and sun tour Friction bar end shifters ,
with the drum brakes, on my studded tire equipped bike..

I think shifting and braking with mittens on would work,
Lobster claw, or 3 finger gloves certainly.

there are external clamp on pods Made for Shimano bar end shifters,
3rd party maker.... if the bar you want is thick walled tube.
so that is a possibility..