Is bitcoin core out of the question? You could import your address to a brand new wallet and just use -walletnotify. You either use an impossible password or pywallet to wipe out the private key.
Bitcoin Core is out because of its blockchain space requirements, I only have 4GB of storage and that won't fit the current 20+ GB of the blockchain. I was able to implement it using Bitcoinj, thanks hhanh00 for your suggestion but I'm considerably more familiar with Java (your project uses Scala), so I guess I'll stick to that (and Bitcoinj).
Thanks again everyone.