The problem of sharing passwords across domains is one of the things that prompted me to write the password-generating service Cryptasia [1].
In short, Cryptasia uses a Google Spreadsheet entirely owned & controlled by each user as a 3rd party data store. Each row contains the friendly name of the site, the login URL, the password generation key, a list of allowed characters, which characters are required, and the length of the password to create. By using the same generator key and character sets, one can have the same password for multiple websites. The password can also be changed for a website without having to change your master passphrase, since just changing the generator key (say, adding a "1" afterward) completely changes the created password.
I know it's not as easy to use as a browser extension, but when I visited Europe it was nice to be able to hop on any computer in one of the hotels and check my email.
I can throw this on Github if anyone's interested (the source-code is all in unobscured JS, too).
In short, Cryptasia uses a Google Spreadsheet entirely owned & controlled by each user as a 3rd party data store. Each row contains the friendly name of the site, the login URL, the password generation key, a list of allowed characters, which characters are required, and the length of the password to create. By using the same generator key and character sets, one can have the same password for multiple websites. The password can also be changed for a website without having to change your master passphrase, since just changing the generator key (say, adding a "1" afterward) completely changes the created password.
I know it's not as easy to use as a browser extension, but when I visited Europe it was nice to be able to hop on any computer in one of the hotels and check my email.
I can throw this on Github if anyone's interested (the source-code is all in unobscured JS, too).
[1] crypt.asia or http://www.cryptasia.com