Yes, anonymity is still achievable, and more backup options are always better.
The strongest point I'd like to make is: retain the password and all unencrypted data within the browser. If you're willing to work on a system to do this, I'm willing to contribute to the open source ajax part of the solution.
I'm researching and working on something along those lines but there are still issues with trying to do encryption within the browser. Not to mention the backend problem.
I would suggest that maybe we can work together on a common browser front end, that would work with different backend. This way, we always have the option to switch between different backend solutions if one proves to be better or worse.