I did look at that, if you look at the last few posts in that thread you linked I actually worked out the database schema from the code. The biggest issue I had with it was that it written in PHP and hence doesn't integrate with the python web framework I'm using for cryptominer.org. Also the integration into p2pool was fairly specific and has drifted from HEAD over time.
Adding support for sub-pools directly into p2pool itself would add value to the p2pool software.
Variance for pools consists of pool variance and share variance. If the pool is only winning one block every 3-4 days, then pool variance is high. No matter how many shares are issued, the total variance can never be lower than that.
The more hashing power on the p2pool chain, the lower the variance for p2pool and that applies to all users.
Even, the major pools would benefit from it to, though granted to a lesser extent. If 2 could be convinced to join, then both benefit from lower variance and reduce variance of all other users of p2pool.
Has anyone considered hierarchical p2pools?
Using p2pool to mine the p2pool sharechain, in the same way people have modified the pool to mine alt-chains.
You could have 1 root chains and 10 sub-chains mining that chain. Each sub-chain has 10X lower difficulty.
The risk of a sub-chain dying increases the more hops from the root chain though.