Classicsat and Djk gave me an idea:
How about a European 50A cooker connector using the American range plug as basis? Take the NEMA 14-50 plug and omit the neutral pin and the corresponding slot on the outlet. Add a flange or recess to the outlet. Voila! Now you have a connector that
a) can provide more than enough power
b) prevents accidental contact
c) works with the American outlet
Intended for 30-50A circuits.
