"The CASS version of the Vaquero - based mostly on looks - is my current favorite, but I"m wondering if the only thing they've changed there is the hammer."
The SASS is a "New Vaquero," not Vaquero, the latter being the now discontinued larger frame gun. My recollection is that the only difference on the SASS is swapping in the Super Blackhawk/Montado profile hammer instead of the high backswept hammer standard on all non-Montado or .45 Birdshead New Vaqueros.
Adding to the nomenclature confusion, Ruger (and distribtors/vendors in turn) have taken to calling all the New Vaqueros just "Vaquero" in its ads and literature. Another oddity, Ruger mislabeled the .44 Special New Vaqueros as just "Vaquero" actually on the frame. All other NV calibers are properly labeled "New Vaquero" on the frame - to date.