In other words you are talking about my second option from my first reply (in bold):
Quote: "Are you talking about texture blending, or vertex weighting as in animated models, or something else? If the first then you could look at the set blend mapping on command."
With that interpretation the answer to your questions
Quote: "My second question which is off-topic, does anyone know of a vertex-blending example or has anyone seen vertex-blending work in DBp?"
are "yes" and "yes".
Most animated models that I've seen use weighted vertices/blended joints and there are plenty of demos around. DBPro supports them natively. I'll see if I can dig up a simple example.
Edit Example attached. It's the "tiny.x" model that comes with the MS DX SDK. Just load the model into DBPro and play the object's animation in the usual way.