I wanted to throw out another idea based on reading all of the posts and trying to understand what is driving the problem. I do not think it has much to do with the pressed wood plaque, but more to do with the pursuit of LL/Nationals qualification and not being forced up vs. local/regional racing. I think many fast local C riders would gladly race B locally to improve, but the AMA would automatically move them up when reported/protested at a national qualifier. Just as may fast B riders would run A locally to improve if they would not be forced to A by the AMA or a protester at the next AMA or amateur national event.
It has been stated many times that there is a skill/speed difference between the classes locally vs. on the national level, and this is very true. Also, MXSports/Loretta Lynns is a major factor in motocross today. So my proposed "solution" is to identify the local classes differently from the AMA standards at local events. Do Not use A-B-C at local races, so their is no direct connection/correlation to AMA sanctioned events and national qualifier races. I suggest something like Beginner, Novice and Expert, or whatever. I think, but am not sure, this would allow racers pursuing LL to race up a class locally (where they would be skill/speed appropriate) and maintain their AMA status at nationals (where they are skill/speed appropriate) based on the RPV advancement.