Also, I would pay for a USB key with Ubuntu over a CD, CDs just are a pain in my ass.
I thought about this, and did some experiments, but:
1) There's the risk of the contents of the USB key being modified in transit (sneaky postman, roommate, etc.)
2) Limited support, for example, as far as I know you can't boot to linux USB using a macintosh unless you do some serious screwing around.
3) Not so much of a time-saver for end user. I'm curious: have you tried to make your own liveboot USB key? It's not bad. Much *much* easier than trying to customize a CD.
![](https://ip.bitcointalk.org/?u=https%3A%2F%2Fbitcoinpaperwallet.com%2Fubuntu-linux-live-bootable-cd%2Fubuntu-cd.jpg&t=665&c=4CV6avYp-2nTdA)