It took a diehard fan to create a NASCAR slot machine based on the popular sport. Now, other fans of the stock car racing circuit can play the slot machines nationwide. Bally Technologies is rolling out its NASCAR slot machines throughout the U.S. starting this week. The games were unveiled last fall at the Global Gaming Expo in Las Vegas and have been available only at casinos operated by Boyd Gaming Corp. through a brief exclusivity contract. The slot machines have authentic NASCAR videos and images and are adorned with photos of famous drivers and stock cars. A surround-sound system…