Graeme ,
I think a site as you proposed would be a step in the right direction for modern Dirt Track as the older guys, using this Forum, have an avenue for their pix and meeting reports etc, however a lot of modern info comes from guys like Fotohound, who has a massive DT email list and forwards modern meeting Pix, Supp. Regs meeting reports etc.
Personally , I am very comfortable with the Forum, as it stands, but the Ning style would appeal more to the young'uns.
Anyway, if something along the lines you spoke about gets a guernsey, it could be brought to the attention of the modern competitors through Fotohound, Anything that lifts the profile of Dirt Track has got to be a good thing, DT is a very important training ground for future World Champions, as it has been proved in the past.
Foss