With the increasing popularity of Apple's iPad, I would imagine more retailers would start to use it as a potential closing incentive. Car dealerships are another example of where iPads have been spotted as promotional tools to get customers in the seats of new automobiles.
An interesting side note on this, Mercedes-Benz has reportedly (subscription required) sent iPads to 40 dealerships, hoping to increase sales by processing sales and leases on Apple's (business) tablet device. The Mercedes-Benz iPad App is designed to keep customers in cars as much as possible, forgoing the back and forth from sales offices. AppleInsider has more on the Wall Street Journal report here.