More on Apple's (AAPL) set-top box: though Apple is in talks with cable providers, no deals have been reached. One issue: cable operators have been obsessed with controlling set-top interfaces. Moreover, unlike music studios, they haven't suffered enough from online distribution to upend their business models. Sources claim Apple's tech could eventually go into in a TV set, and prototype sets have been developed - past rumors have suggested pay-TV providers are testing them. But squabbles over control and content deals could get in the way here as well.