No, for realz. There may be other approaches, but the specific materials used in the video you linked to were all designed explicitly to support vertex color-based blending. Unreal lacks the concept of multipass rendering for materials outright.
Are you completely sure of that? An artist told me that he could blend separate materials in UDK and asked me if I could do the same in Unity. Of course, "material" is quite a high-level concept which differs in UDK and Unity, so I was wondering how this could actually be done technically in UDK.
EDIT: In fairness, I think lighting is done multipass, but this is not something you work with as an artist. The material compiler generates a lightmap-lit shader for 'ambient' and point light additive shaders.