Does it have to be the BIP32 HD setup?
Because someone made a clone of the old Blockchain Receive Payments API V1(blockapi.net) where you just use a GET request. Provide an address and it returns a fresh address for receiving payments, and will send a callback to the URL you specify. Works exactly like the old service used to, except this one charges a 1% fee on each transaction.
Example:
http://www.blockapi.net/api/receive?method=create&address=1YourBTCAddress&callback=http%3A%2F%2Fmysite.com%2Freceive
I appreciate the suggestion, but I do need it to be fee-free. The importance of BIP32 HD is also very important, as I need it to be going to cold storage so that disasters can't happen with people stealing funds from the hot wallet, or being intercepted from the payment processor.