This Instructable uses birch plywood and a lift by Firgelli Automation to implement the design. The TV shown here is a 60" Samsung but could be any modern flat screen. It includes shelving for your components and drawers to store Wii remotes and DVDs/CDs.
The step by step pictures show key parts and there are over 40 minutes of video with tips and tricks as well. The total cost is around $1000... not including your TV.
There is also a set of shelves to go above the lift cabinet listed here: TV Lift Cabinet - Shelves