Say I am using an online wallet that uses BIP32 deterministic keys and the site goes down. I have a backup of my seed (passphrase). Is there a github repo that I can download, run on an offline computer, present it with my seed, present it with the BIP32 Path: m/44'/0'/0'/0/2 and recover the private key associated with that seed/path so that I can transfer the funds out of it?
Here's a web tool for BIP32 key derivation.
The only problem is the hardcoded 50k rounds of HMAC-SHA256. You do need to know how your wallet software exactly derived the master private key from the mnemonic or you'll get totally different keys. Unfortunately there's no standard convention for the HD wallet backup/restore process and I'm afraid this ranks quite high among the biggest downsides against Bitcoin adoption.