You are stuck with the 4 speed or the 730. Zero room to adapt anything else into that Vdrive configuration. As far as I know, even the rear diff and axle is an orphan specific to the application so even a 2 speed diff is a no go. That would be the easy button solution if it used a generic Eaton or Rockwell axle.
At least the Scenicruiser is a T drive so you have a few transmission options that have a few more gears but are short enough to fit the space.
Kevin
No multi-speed V drive manuals by anybody other than Spicer that fit? yikes - didnt know that. I was sure there was something by somebody
guess its this big honkin' thing (the V730) .. but i really dont wanna do an automatic