This one keeps this and sends event object as the first argument (no more checking!). It also has only one parameter or parameters maybe- the argument/s you want to send to your function. Thats it! Bonus: the last argument is the co-ordinates of the event.

// Function.prototype.toEvent, .bindAsEventListener( args ) REM2006 for this.js Api  
// Important: sends event as the first argument to your function in IE also!, 
// event XY [Array][x,y] is passed as last arg, your passed args are in the middle :)
// example: myElement.onclick= myFunc.toEvent( myArguments ); http://richard-m.blogspot.com/
//  
Function.prototype.toEvent = Function.prototype.bindAsEventListener= function(){
  var _method= this, r=[], len=arguments.length, i=0;//alert(len)
  for (i;i<len;i++){ r[i+1]=arguments[i] }
  return function( ev ){  r[0]= ev= ev || event; 
    var db=document.body, dd=document.documentElement;
    r[r.length++]=(ev.pageX)? [ev.pageX, ev.pageY] : 
      [ev.clientX + db.scrollLeft+ dd.scrollLeft, 
       ev.clientY + db.scrollTop + dd.scrollTop];
    return _method.apply(ev.target|| ev.srcElement, r);
  };
};