Agree with NothinG.
I am going to open my pool to some of my friends, so I need to test if miner's own bitcoin address is working. That's why I use bitcoin address as miner's name.
Now it seems working, but they can't easily find their own statistics.
Hm.. Is it possible for you to use the "-a" argument to p2pool to set the address instead of the miner username? The miner username is only really useful if you have a public p2pool node that others mine on.
It would be cool if miners had their own personal graphs and JSON.

Like:
http://poolnode.com:9332/graphs/{minerID/btcAddress}.html