Per wheel steering, ackermann, caster are in trunk(2811).
I've set F1-02 to 50% ackermann. Ideal ackermann(steering arm angle) for a rear axis turn center(slow speed) would be atan(0.5 * steering axis width / axes distance). Other cars have zero ackermann at the moment.
More info on this topic:
http://www.smithees-racetech.com.au/ackerman.html
The only thing left are the differentials(link wheel to differential axis). Then we should be able to support an arbitrary number of wheels. There are still some issues with wheel/suspension simulation. Will try to fix them asap.