Well I think part of the problem is, its rare to find an actress who either IS already a pretty decent hardbody to convincingly pull of a 'super-chick', OR is committed enough to the role to get in shape. I know SOME will do it, some are more concerned about going clubbing or outrunning TMZ.
Well, perhaps a professional actress is not what we need.
I mean, seriously: how much range would someone need to play Red Sonja?
Perhaps instead, casting directors should take a look at women athletes and bodybuilders who are interested in giving acting a try.
You know--like Schwarzenegger.