You can probably get a dashboard from a dismantler. I recall seeing plenty of them on fleabay. However, this is not a job for the light hearted. If you don't do it right, you'll get a bunch of rattles in your dash while driving down the street that will drive you batty. Also, you need to be careful when working around the airbags (make sure you disconnect the battery) for you don't want the airbag to deploy in your face while you're working on the removal/replacement.
I've seen someone use black leather dye to recolor their grey leather to black. Maybe that route would be easier than pulling out the whole dash and replacing. Just a thought. However, this would only work if your dash is leather and not vinyl, as the vinyl would not absorb the dye.
This fella used black leather dye to make his car look like it has a two-tone black/grey interior, making the middle section black, and also parts of the steering wheel and upper dash pod (although you can't see it in the pic there).