[Chuck Moreland]

I've no direct experience here, but seems to me a straight "you break it you bought it" could be problematic. What happens when the car is balled up and totalled? The renter has to come up with $40-$60k?

That's a tough pill for the renter, and maybe you too. Signing the contract is one thing, collecting after the event is another. You might get burned, or tied up in legal battle, or both.

I would think about taking out a policy to cover the damage, with a sizable deductable - perhaps $5k. The renter is liable for damage to the extent of the deductable and you collect it up front as a fully refundable deposit.

That caps the renter's liability to a reasonable level, yet gives incentive to drive responsibly. You too are covered because collecting on the insurance should be easier than from the renter. Plus you've got the deposit up front.