There's been a lot of speculation about an Apple HDTV of some kind, but it's much more likely that an improved Apple TV will make it to market before we see a large flat screen device. CNET is reporting that supplies of Apple's diminutive black box are dwindling at brick and mortar stores across the U.S., possibly pointing to a refresh of the Apple TV. BestBuy.com and Walmart.com are no longer listing the Apple TV on their sites, and the only Apple TVs available on Amazon.com are used devices. AppleInsider reports that