I don't think you are going to find anything that new, or that short, for $80,000 that will ride better than your C. That price and length barely gets you into A gasser (or front engine diesel) built on the same chassis as your C, or Sprinter Chassis, or lightest version of Ford's F-53. Short wheelbase and metal springing will mean a rough ride.
For a best ride, you should be looking for air suspension, 36-40+ length, preferable Spartan or Roadmaster (8 bag) chassis, although even a Freightliner should ride somewhat better than E-series or F-series. Thus you would be looking for something used, and fairly old to bring a $200K to $400K coach down to your $80K budget.
