“Brainwallet” is a program that takes a passphrase (hopefully a good one) and deterministically creates a Bitcoin wallet. This wallet can be used for transactions, then deleted from the computer. To get access to the wallet again, you only need the passphrase to re-create it.
Does something similar exist for GPG? If yes, where can I get it?
If not, is it even possible to create such a program? Maybe it's just a bad idea?