A calculation like this has already been made in the bitcoin presentation
Why you should invest in bitcoin. Tuur Demeester calculated that the value of one bitcoin would be $500,000 if it takes over the entire world's financial system. I'd like to the exact part of that presentation, but I didn't make a mental note of where in the presentation he said that.
The "good stuff" in Tuur Demeester's presentation is a little after 26 minutes into the presentation.
Not to say that the entire presentation is not good. It is just pretty nice to see good reasons for the price to be valued so high.