Will putting a ferrite bead or beads near (but not at) the end(s) of a wire antenna electrically lengthen or shorten it? (lower or raise its resonant frequency)?
Lengthen. The bead increases the inductance, similarly to a loading coil. Near the ends the current is low, so the effect is diminished compared to the same coil near the feedpoint.
I wouldn't recommend it for a transmitting antenna. Ferrites have significant loss, and may saturate. Non-linear components are definitely not something you want in a transmitting antenna.