An iMac-TV? No chance. I don't suppose any of these 'analysts' or individuals whose brother's-friend's-sister's-daughter working at Apple has thought that it would require another OS on top of, or part of, Lion?
If were being ultra realistic here (or more critical), these insiders have only started cooking up rumours and predictions because Steve Jobs suggested in his biography that he had "cracked" whatever it was which was holding Apple back from releasing a TV.
Note he said "cracked", not we've "cracked it, and were going to release a TV". I could easily say I've cracked the solution for time travel, but I won't be retro-fitting a DeLorean any time soon.
Apple won't produce a TV in the near future for the simple reason that they themselves know, within such a competitive and mature market, it would be ridiculous to try and sell a product that costs almost twice as much as competitors just because it has a picture of a fruit of it. Forget extra features such as streaming, downloading or 'the cloud', people these days can get content on the television set however they wish.
Whats more, the quality of TV are the components themselves. Unless Apple are going to contribute something to panel development, the end product isn't going to be much better or worse.