For rentals, RAV & Dream Cars are the two big players in town. If you want to do a 24 hour with Dream Cars, you can find a link to get 10% off on the coupon page I mentioned in This Thread

If you're really shopping, why not get in touch with Penske-Wynn Ferrari Maserati at Wynn Las Vegas

Fill out one of their sales inquiries & maybe they'll let you take one for a spin. There's a private drive from the dealership out to LV Blvd. made just for that.