Edit in JSFiddle

(function(){

    Math.guid = function(){
        return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c){
            var r = Math.random()*16|0, v = c == 'x' ? r : (r&0x3|0x8);
            return v.toString(16);
        }).toUpperCase();
    };

    var Model = {
        inherited: function(){},
        created: function(){},
        prototype: {
            init: function(){}
        },
        create: function(){
            var object = Object.create(this);
            object.parent = this;
            object.fn = object.prototype;

            object.created();
            this.inherited(object);
            return object;
        },
        init: function(){
            var instance = Object.create(this.prototype);
            instance.parent = this;
            instance.init.apply(instance, arguments);
            return instance;
        },
        extend: function(o){
            var extended = o.extended;
            jQuery.extend(this, o);
            if(extended) extended(this);
        },
        include: function(o){
            var included = o.included;
            jQuery.extend(this.prototype, o);
            if(included) included(this);
        }
    };

    Model.records ={};

    Model.extend({
        find: function(id){
            return this.records[id];
        }
    });

    Model.include({
        newRecord: true,
        create: function(){
            if(!this.id) this.id = Math.guid();
            this.newRecord = false;
            this.parent.records[this.id] = this;
        },
        destroy: function(){
            delete this.parent.records[this.id];
        },
        update: function(){
            this.parent.records[this.id] = this;
        },
        save: function(){
            this.newRecord ? this.create() : this.update();
        },
        init: function(atts){
            if(atts) this.load(atts);
        },
        load: function(attributes){
            for(var name in attributes){
                this[name] = attributes[name];
            };
        }
    });

    var Asset = Model.create();

    var asset = Asset.init();
    asset.save();

    var asset2 = Asset.init();
    asset2.save();

    console.log(asset.id);
    console.log(asset2.id);

}());