i can see your point re. theives and scammers, but no matter where you go you get them, even on autotrader and pistonheads. Its just the case of being careful.
I personally feel if a for sale subsection was added with links to the website where it is advertised would be very handy, mainly because i would be quite attracted to a car that has been enthusiast owned and maintained. Atleast it gives you an idea of the type of owner, and if they have posted a blog on the forum, the potential buyer would be able to see the progress and maintenance of the car.
Just a thought..
Jack