Before someone gets the bright idea to use an automotive electric window regulator for a TV lift, bear in mind that the TV lift is obviously much heavier in construction than its automotive cousin (unless you are driving, say, a bullet-proof Hummer, car windows don't normally weigh 200 pounds

).
There are numerous IR/RF universal remotes on the market, ranging in price from about $50 to well over $1000. There are also RF to IR converters that can be placed inside the credenza. These receive an RF signal from the remote and relay it to the TV as an IR signal, usually with the aid of a mirror mounted inside the cabinet.
Another idea I had was to use an IR repeater in conjunction with a motion sensor mounted inside the cabinet. When the motion sensor detects movement from the lift, either up or down, it sends a signal to turn the TV on or off. The signal for on or off is the same as it is simply a toggle, changing to the opposite value (if its on, turn it off, otherwise turn it on).
Several companies have very inexpensive motion sensors and IR/RF repeaters.
Another solution would be to mount an IR receiver "eye" somewhere in the millwork of the cabinet. One could pretty easily cut an opening between two "teeth" in dentil molding and place a thin smoked lens in the opening.