Possibly mixing prototype and module pattern

I have either created something beautiful or something monstrous, and I'm not really sure which, and I don't know where else to turn but here. What I've done:

var MyObject = function(opts) { 
    //init code, set vals, runs when 'new MyObject()' is called
}

MyObject.prototype = (function() {
    //private helper functions
    //scoping is a pain, but doable
    function myPrivateFunction() {}

    return {
        publicFunc1: function() { /* uses myPrivateFunction() */ }
        , publicFunc2: function() { /* uses myPrivateFunction() */ }
    };
})();

MyObject.prototype.publicFunc3 = function() {}
MyObject.prototype.publicFunc4 = function() {}
MyObject.prototype.publicFuncEtc = function() {}

To my surprise, this works, and takes care of a pretty significant problem of creating reusable private functions for various public functions. Of course, I have to do some scoping for the this object, but I feel it's a small price to pay for being able to use private reusable functions. I left the other functions on the outside to avoid having to deal with scoping.

My question is: is this a code smell? and as a corollary, is there a better way to do this?