If I were doing this, I would first cut out the "P" (I would do something different, but that's just me), with a dremel and then sand the edges to make a smooth symbol on top.
I would then cover this hole with plexiglass (or any other clear substance that would work to make a window), so it's not just an open hole.
I would put a few LEDs around the logo (on the underside of the lid... wired in parallel), so that the LEDs light up the window, thus illuminating the "P" (or whatever).
I would then take the + and - leads from my LEDs (in parallel), down against the lid (underside) through a small hole into the main console (you may need to drill this hole yourself, unless there is one already there you can use).
Once the leads are inside the console, I would probably power them by soldering the leads to the + and - contacts for the PSX power-LED (since it should suppliy the right voltage without the need to add a resistor to your LEDs.
I hope you can understand what I explained above... And I hope you get this mod done the way you would like to.