It should be possible to crawl the blockchain for which address has mined each block. I could probably script this if I could build a local block explorer...
That may be as close as you're going to get though - just as it's impossible to assume true coin distribution via address as someone can have multiple wallets/addresses.
That may not be that easy either TLC. I've noticed that my own rig uses a different address for each block thus far. I'm throwing about 1.3 Mh at the network and the couple blocks I've found, each have a different addy. I never set up a dedicated addy for mining in the config file by the way.