I guess the thing I'm looking for, rather than buying yet more software, is to find a way to get my existing models, all of which are already set up to render directly to Maxwell or Vray, animated.
The nice thing about Maxwell is that it translates SU materials to Maxwell MXM files and the MXS it creates can be opened into Maxwell Studio for further refinements and rendered from there. If Vray created a file I could open in 3DS Max I would be all set, but lo, Chaos seems to like to complicate their software with incompatible material types and a distributed rendering system that defies all logic. I guess they earn their name.