After a little more research, this seems to be reported in suse, at https://bugzilla.novell.com/show_bug.cgi?id=206641 - sounds like a deadlock in the kwallet integration code.
There didn't seem to be an upstream report, so I've filed http://bugs.kde.org/show_bug.cgi?id=136469 -- knetworkmanager freezes if kwallet doesn't open immediately https://launchpad.net/bugs/69118 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
