You could try these guys. About as shallow depth as I've found.
[Link: tvliftcabinet.com]The lift itself (mechanism) is about 3" D, but then has a shelf lip that the TV sits on which is 3.25" D.
I'm using one of these now in my custom built-in banquet in my kitchen. Certainly not as quiet as I'd like or used to with other more $$$ manufacturers. It was the only one I could find that would fit the dimensions I needed for the box.
But it does get the job done and the 110V auto-operation is neat because I did't have to add it in my C4 system.