The best thing is for a 4 layer but you can use a 6 layer I you can deal with the extra heat and power consumption, but if you buy a wii for the project try finding a 4 layer.
I don't know if you have tried this but sometimes i'll search for screen combos (screen and driver) that have a similar if not the same screen and buying the driver from that combo. I usually search by screen type, resolution and inches.
hope it helps.
Edit: I was looking and it seems a 24 bit...