Just curious, surely there are numbers and a graph of distribution out there?
It is not possible to know that because there is no way to know how many bitcoins a person owns. You can easily find out the distribution of bitcoins per address, but there is no way to translate that to bitcoins per person because most people have multiple addresses.
There is a poll here:
https://bitcointalk.org/index.php?topic=164662.0I doubt its accuracy, but it is probably your best source.
To collect the data required to do this would mean finding the balance of every single Bitcoin address.
Is that even possible?
If it is possible it sounds very difficult.
It is not difficult because that information is in the block chain. That is how a wallet calculates its balance.