Could be... could be... I'm thinking in terms of the Rallyists I know. I don't think "non-competitive" is in their vocabulary, even the few that drive Historic cars.
Anyway, as I said earlier, the way to do it would be to work with the existing rally sanctioning bodies and local rallying organizations. They have the experience of putting on motorsports events outside of a dedicated racing circuit.
I should think you would need to present them with a pretty good business case though and have some eligible roads lined up.
Insurance would be "interesting" to say the least...