A Raspberry Pi costs $35 and can sufficiently run an offline Armory install. It's a cheap and effective solution.
- you scan a key with only 10 BTC on it so this is the maximum loss.
- you can use lot's of different computers and mobile phones and tablets to process your transactions
- rPi method is interesting, similar approach is undertaken by Slush & team with their hardware wallet, however their method and all methods that deliver security via dedicated hardware is the following:
1. let's say I would like to transfer 1000BTC to mtGox in hopes of selling the coins. With your approach I would open mtGox account from my online computer, generate bitcoin receive address on my mtGox account and then proceed to sign the transaction on my "offline" rPi super secure device
2. you see where I'm heading?
3. a black hat hacker does not need to hack into my super secure offline rPi device. All it needs to ensure is that the receive address displayed on mtGox account is not the receive address of mtGox but rather one generated by hacker who now receives coins on an address he has secrect key for. In order to do that hacker would "only" need to hack into an "online" computer which by your definition is possible.
If your argument is that you'll discover whether the 10 BTC goes to the intended receiver, then just start out by signing a transaction - with the offline wallet - for 10 BTC to the supposed Mt. Gox receive address. If this goes through to your Mt. Gox account, you can proceed to send the remaining 990 BTC.
Imagine having to import keys from 100 different 10 BTC-paper wallets. Now that would be tiring.