Is there a way for me to use my xbox360, ps3, or wii, to mine for bitcoins?? Some sort of code written to be like a game, but actually is a miner.
Yes.
I would think that a gaming console would have the highest hash rates of them all.
No.
When Bitcoin was CPU mined consoles were pretty powerful compared to home computers. However GPU destroyed those perfromance metrics. Remember xbox360 & PS3 are now what 7 years old? That means the hardware (which was finalized about 2 years before launch) is almost 9 years old.
It would be like saying I think a low end video card from 9 years ago would be a powerful miner. Moore's law is a monster. Even if a console is top of the line (which usually they aren't) a decade in an insanely long time. GPU performance roughly doubles every 18 months. An entry level video card today (i.e. $59 special) is many magnitudes more powerful that the most powerful GPU from 10 years ago. Worse the GPU on consoles can't be used at all. They come from a time before programmable shaders. They can't run OpenCL code.
Hypothetically shortly after launch of the "next xbox/PS" they may be decent miners depending on how powerful their GPU are and if they are OpenCL capable. No way to know until they launch. Today PS3/xbox is worthless for Bitcoin. Maybe someone could look to see if they can mine "CPU friendly" chains. A lot would depend on how much L1 cache they have. My guess is they won't do a very good job there either.