Define the purpose you have in mind.

Go fast racer .. with really low handlebars? or pootling along tourer with higher bars..

you havent even tapped into the Travel and folding bike sector, like Oregon's Bike Friday
there the size is top tube length , a torso~arm reach - length determination.

And the height of Bars and seats are on masts that are made at the time you order the bike,
as is the whole bike, but if you change your mind, they can be replaced.