In a recent discussion about the future of KDE’s password manager KWalletManager it was mentioned that it is currently discussed to share a common password manager across all important FLOSS projects. While there is no result yet this is indeed a promising – and necessary – development.
It started with a question by Michael on the list kde-core-devel regarding the possibility to switch KWalletManager’s backend to the Qt Cryptographic Architecture (QCA) entirely. Robert answered that there was indeed discussion going on during FOSSCamp to merge all existing solutions (KDE, GNOME, OpenOffice, Firefox) to make it easier for the user to use these applications, but also to have the ability to sing-sign-on (meaning one login as user, and than automatically login everywhere else), which is a need for modern desktops. Afaik Fedora also has this topic on its radar, and it would surprise me if no one at OpenSuse, which constantly tries to bring these two desktops closer, has already put some thought into that.
While there are no visible results currently the need for such a solution is definitely present: At the moment it can happen that there are multiple programs used to store different keys in one single user session: Firefox on KDE introduces for example a second key storage right besides KWalletManager. Since the Open Source world does not want to force any solution on anyone, it should be possible to switch between Konqueror and Firefox without the need to take care of your passwords.
Technically there is no reason against a shared password storage, but it might tricky to convince the application/desktop developers. On the other hand, if KDE would get a pluggable KWalletManager backend it could even become possible to use the native key storages on other platforms if such APIs exist.