A turbine-generator combination would be a very good interim solution until fuel cells has matured.
IIRC it has already been used in a few prototypes, most notably one built by Ferdinand Porsche (sans turbine) in the early 1900s.
The efficiency of the whole torque to current to torque process isn't very good yet, but it can be very light and small (a turbine that runs at a constant RPM can have very good weight/size to power ratio) and there isn't any loss to gears and transmission if electric hub motors are used. That could make up for the efficiency issues.
IIRC it has already been used in a few prototypes, most notably one built by Ferdinand Porsche (sans turbine) in the early 1900s.
The efficiency of the whole torque to current to torque process isn't very good yet, but it can be very light and small (a turbine that runs at a constant RPM can have very good weight/size to power ratio) and there isn't any loss to gears and transmission if electric hub motors are used. That could make up for the efficiency issues.