Madmax,
I too own a M4300 and have struggled with the black screen. I followed some of your posts and tried a few things. I *think* I've finally got rid of it when I did my Mountain Lion install. I edited my DSDT (in our bootpack).
From this:
"device_type",
Buffer (0x0D)
{
"NVDA,Quadro"
},
"model",
Buffer (0x18)
{
"NVIDIA Quadro FX360M"
}
To this:
"device_type",
Buffer (0x0D)
{
"NVDA,Parent"
},
"model",
Buffer (0x18)
{
"NVIDIA Quadro FX360M"
}
So far, so good -- I've yet to have the black screen.
HTH!! Good luck!