score:5
I just found a Tesla Model S ("or similar", which is what they put on every car, but they say they'll contact you to confirm after you book) from Sixt searching for a pickup from Frankfurt Airport (I randomly used 06/20/2016-06/22/2016) for a mere US$360.71/day.
So they appear to have at least one for rent. Whether it's available under the exact terms you want is something you might need to contact them about.