sorry to sound stuck up or rude, but getting into law doesn't actually seem too difficult, at least not when you compare it to med. whilst straight law is quite hard (99.35 for 2010 entry to monash), the double degree option brings it down to low 98's, which is quite doable if you put in the effort.
and really, it is one extra year via a double degree as if you don't get into straight law then you have lost a year anyway. and honestly, if you want to do law, then just take the double degree. at least you have guaranteed yourself a placement. i would kill for a guaranteed med placement, even if it took 2-3 years longer.
moreover, if you're passionate enough about law, then as I previously said, you would jump at the idea of getting the opportunity to study it, even if it takes slightly longer to graduate.