Unfortunately, it doesn't look like there is currently a way to do this (at least neatly in the namespace area). Layouts are searched in the controller-extensions library, where the controller's name is used to search for a layout, then it defaults on the application layout.
However, it is possible to define one layout to be used between several views. You can use the layout
function at the top of a controller to change the layout. For example, I can define the layout app/views/layouts/reports_layout.ejs
for the reports namespace.
Example namespace:
map.namespace('reports', function (reports) {
reports.resources('billing');
});
Controller:
layout('reports');
action('index', function () {
this.title = 'Billing Report';
render();
});