Actually there are 6 inputs and 1 output, just click the "show inputs and coinbase" link on blockchain.info.
The number of inputs is not the number of wallets the money comes from; it's the number of transactions the money comes from.
Yes you are missing something. Press "Show scripts & coinbase" and you'll see that the transaction has 6 inputs.
Thanks. I've been relying on trezor.io to tell me my transaction size before hand this whole time.