I'm wondering if the size of most miniatures would preclude painting wrinkles.

Painting them on is beyond my abilities, alas. I can certainly get a weathered look with the right use of ink, as here, but that depends a bit on the figure and I haven't managed to achieve it with pale skin yet.

The other problem is that even if I could take care of the faces, the bodies generally aren't right - stuff like this, for instance, doesn't really look right for an elderly character. Still, I might be able to do something with some of the more static poses...