Well, it took me a few nights, but I'm finally getting the hang of rigging models for animation in Shockwave3D. It's a lot more difficult than I thought it was going to be. I ended up rigging and re-rigging this model about a bazillion times. But I finally got it right with a fully-animated run cycle.
You can see this rigging test in action if you like. It lets you see Luthien running, and you can view her run cycle from pretty much any angle.
There are still some issues with the model and animation that I need to fix, but this is a workable placeholder. Things I'd like to fix are the leg showing through the dress on some frames, bringing the legs closer together for the run, and adding some animation to the hair to make it bounce. But I'm happy with it for now; I want to get back to making scenery and engine-level stuff.