In the meantime you can buy a USB stick with an AVR, flash memory, and two buttons on it for about $10. That's probably the easier route, and since they're sold mainly for non-bitcoin applications you don't have to worry quite as much about being trojaned.
Surely you mean cheaper, not easier.
Yep. That's exactly why you should only buy one of these things if it specifically isn't marketed as a bitcoin-related device. Catch-22.
Can I assume that you also make your own OS and bitcoin client?