My local independent mechanic who services my Ferraris and Lamborghini does several long distance PPIs per year. I don't think it's uncommon to not let any unknown parties leave with the car. Most of the time when I have shopped for cars, the dealers have either offered to transport the car themselves to the shop I chose for the PPI, or offered to let someone from that shop pick it up since the insurance liability then transfers to that shop.

My approach has been to ask if I can send my mechanic over to do a PPI. It's a little less cost effective with a $35k Jalpa than a $150k Diablo, but a Lamborghini is a Lamborghini and my thought is that buying my local mechanic a plane ticket and paying him to do a thorough PPI (that he will have to stand behind if the car comes home) is money well spent. If the car isn't a keeper, I've laid out less than $1k to save 10-20x that in repairs on a bad car.

As I said, several of his clients pay my guy to do that on a regular basis, and since the Lambo community is small, odds are that my guy knows their guy and will get some professional courtesy that you might not.

Just another tool to add to your basket while you're shopping! Good luck!