Some time ago, I had downloaded some objects by Alopex at MTS cloned from the pushable statue. I had long thought about using the bookcase in a study to conceal a hidden passage. I also wanted an upper loft now that we have the circular staircase (as lame as it is - whose frackin' idea was it to put the floor around the top by default?) with Generations. This is how it turned out (disregard sims' costumes):
The main floor
The upper level
I made it hidden so the sim had to "inspect" it to determine it's pushable status.
I may have to incorporate this into a house sometime! :P