A partner at my firm has the Tesla. It is a fantastic vehicle, truly a "game changing" vehicle. Ridiculous instant torque, no shift shock at all, compared with other great luxury cars where you can feel a "slight" shock. I would probably consider it, but would be more interested in future generations.
If it were my money, and I'm not in the market for a near six-figure luxury sedan (though I wouldn't mind if I were) I'd narrow it down as follows:
Mercedes Benz S-Class, current (deal on existing inventory or CPO) or next generation, which I guess by looking at the preview info online could be even better. I've driven a current model S550. An amazing car in every way.
Porsche Panamera. Truly a Porsche sports sedan, but the exterior is...an acquired taste. A deal breaker is that it's only a four passenger ride, and I think for a large luxo-barge, to truly spread out the center rear seat would be the way to go.
Or, a Lexus LS, probably CPO. It is bland by comparison, but still very solid, reliable as the sun rising in the morning. Gives you about the same level of luxury, very comfortable.
Ah, and this is where my frugal roots betray me. My money? I'm good with a Toyota Avalon. Comfortable highway ride, and I have 50-60k to spend elsewhere. But then, I'm a cheap [censored]. If I had the money, those three above would be my finalists for large luxury sedans.