Heres a good link on this stuff:
http://www.ozebiz.com.au/racetech/theory/align.html
Yes some Toe-out on rears for genuine FWD race cars is possible.
If you have been driven hard in a FWD race car on track by a pro, you will realize that essentially the rear is set up to be unbelieveably loose, its like a shopping trolley at the back.
Not really something you want when slamming on the brakes on a blind corner on a wintery evening when you notice an accident ahead.