Faraday Passport Holders, eh?
Your joke startup has already been going for a few years: http://www.difrwear.com/product-display.php
The real joke? I bought one for research purposes. They're quite smart and attract glances from all the ladies in horn-rimmed glasses. Additional room inside for a few RFID enabled Oyster cards and the number of the beast. I'm going to play around with it over the next few weeks and see how well it shields the passport, the Oyster cards etc.
Here's a crazy thought: how about including a momentary touch switch in the RFID passports which requires the individual reading the card to hold it down, to complete the circuit to the antenna, so that it responds to the card reader? No operator, no response. Oh wait, no. That's sensible.