I always loved the RDs. Something different could be a load of bikes though. Honda 750 F2 was a nice bike. Small two strokes vs larger four stroke? Price and availability is next.
What about an RD350 that you ride - restomod it. That appeals to me. Get something that runs and ride it.
Really want to try something different. Even the RD350 which never appealed before has been entering my thoughts.