They were legal in BRCA (at least last year) and are too this year
(Let's keep it that way unlike the IFMAR, after all FWD is also 2WD) - The only difference is that they stated this year that the
driven wheels on a 2WD have to use 'rear' (=wide) wheels/tires, whereas last year it stated
rear wheels.
The new regulations even out any advantages for an FWD in choosing any front tire, but also allow me to run a rear end without using worn or cut tires (you don't need a big load of rear bite to keep the car stable).
Edit: I thought I'd share this link to show you FFs are good fun :P
http://www.youtube.com/watch?v=RwbeRkIuSUc