[SOLVED] Thanks stworthy! For others and future reference, here is a function that returns a tree node's element using the node's text:
/**
*Retrieve tree node element using node list item <li> text
 *
 * @param {easyUI.Tree} tree easyUI tree object
 * @param {string} nodeText list item <li> text of desired node
 * 
 * @return {element} the tree node <li> element
 */
function getNodeByText(tree, nodeText) {
	var mynode = null;
	var roots = tree.tree('getRoots');
	$.easyui.forEach(roots, true, function (node) {
		if (node.text == nodeText) {
			mynode = node;
			return false;
		}
	});
	return $('#' + mynode.domId);
};