There are apparently many short films on youtube made by fans where they pit heroes and villains from different stories against each other. A lot of them are cuts from various movies stitched into an order to make up a plot or trailer. This video actually has them fighting which is AWESOME.

I assume that a predator would win in most situations especially if he is the one to initiate combat since he would blast Batman with his gun. The predator is also much more bad ass than Batman. Maybe if Batman had some prep time he could over come a predator but of course the rest of them would come and destroy him.