Hello,
I have just finished implementing the private-key half of BIP 32,
"Hierarchical Deterministic Wallets". The code needs a lot of cleanup,
and I need to finish private key path, but at least what's there now
is producing correct results. I have placed the code in the "bip32"
branch of my personal libwallet github repo:
https://github.com/swansontec/libwallet/tree/bip32

>From what I understand, I am not the only person working on this, so I
want let folks see what I'm doing to avoid duplicated effort.

-William