So, in less than a few hours, I completed the password store component for Joomla. That's partially because I worked from a different component that had most of the options I needed, but partially also because I could easily use the Joomla infrastructure, which requires little in the wake of learning.
Of course, while it's a functional component, it's still not at 1.0. Hardcoded strings (they are in the original, too), incomplete removal of spurious options, you know, that stuff. So I'll continue cleaning up for a bit, then publish.