if the only reason you like __proto__ is its literal integration, just use this and make the web better today. No credits needed

O.js

// ES5 dirty perf oriented tweet size
var O=function(O,s){s=O.setPrototypeOf||function(o,p){o.__proto__=p;return o};return function(p,o){return o?s(o,p):p||s({},p)}}(Object);

// ES5 dirty performance way
var O = function(Object){
  var
    create = Object.create,
    set = Object.setPrototypeOf || function(o, p) {
      o.__proto__ = p;
      return o;
    },
    undefined
  ;
  return function (p, o) {
    return o === undefined ? (
      p === null ? create(p) : p
    ) : set(o, p);
  };
}(Object);


// ES5 full compliant way
var O = function(Object){
  var
    oProto = Object.prototype,
    create = Object.create,
    has = oProto.hasOwnProperty,
    undefined
  ;
  return function (p, o) {
    var r, k;
    if (o === undefined) {
      o = p;
      p = p === null ? p : oProto;
    }
    r = create(p);
    for (k in o) {
      if (has.call(o, k)) {
        r[k] = o[k];
      }
    }
    return r;
  };
}(Object);

examples

var n = O(null);
n instanceof Object; // false


var p = O(Array.prototype, {
  has: function (v) {
    return !!~this.indexOf(v);
  }
});

p instanceof Array; // true

var o = O({
  justObject: 1232
});

o instanceof Object; // true

var m = O(null, {
  my: 'dictionary'
});

m instanceof Object; // false
m.my; // dictionary