While I havn't tried it yet, you should be able to boot it off an iPod.
And if you have a 40gb iPod... thats a LOT of room for any steam games ya want
I'll do a TFC on iPod test later today.
This may also help BC if you can run it while pluged into the firewire, it will work with older computer that don't have USB 2.0 but firewire. (They have USB 1.1 but I couldn't run it off 1.1
)
And as for USB thumb drives, I've got one 1gb USB 2.0 and atleast 2 or 3 128mb USB 1.1. I may get my hands on a 256mb USB 2.0. I also have one thumb drive that has a bootable version of both Firefox and Openoffice just incase I need to work on a computer without FF or a version of Office...