Snippet to add a root node to layout in Magento. This would be placed in local.xml (or page.xml).

gistfile1.xml

<?xml version="1.0" encoding="UTF-8"?>
<layout>
    <default>
        <reference name="root">
            <block type="core/text_list" name="new_root_node" as="new_root_node" translate="label">
                <label>New Root Node</label>
            </block>
        </reference>
        <reference name="new_root_node">
            <block type="catalog/text" name="some_block" template="page/html/some_template.phtml" />
        </reference>
    </default>
</layout>