asyncparser.js

// untested poc/theory code
define(["dojo/parser"], function(parser){

    var asyncParser = function(rootNode, oldSupport){
        // summary: An asyncronous 
    
        var dfd = new dojo.Deferred(),
            deps = dojo.query("[dojoType], [data-dojo-type]", rootNode).filter(function(n){
                return (n.getAttribute("data-dojo-type") || n.getAttribute("dojoType")).replace(/\./g, "/");
            })
        ;
        
        deps.push("dojo/ready!");
        require(deps, function(){
            dfd.callback(parser.parse(rootNode))
        });
        
        return dfd;
    }

    return asyncParser;

});

// usage:
define(["dojo/asyncparser"], function(parse){
    dojo.when(parse(), function(){
        alert("all widgets insantiated");
    })
})

it looks like a reasonable poc for how i'd imagine it might work.