I say this having never driven a Tesla, but are they really suitable rental cars? My understanding is that Tesla vehicles differ quite a bit from regular ICE vehicles, to the point that there's a bit of a learning curve to operating the car. I'd be interested to hear from a Tesla owner on this. Maybe it's a non-issue.
My concern with renting one (which for now would stop me from doing it), is the scarcity of charging locations. Not sure how far apart they are in most locations nowadays, or what wait times are like, but if I'm on vacation (which is when I most often rent), then no hassle is worth it. There are gas stations everywhere.
Tesla's navigation software will show charging locations, as well as add stops automatically if you're planning a route that's too far for the current state of charge.
Plugshare is a good site for finding chargers of all types.