Allow each item in a PanelBar to be named via Name() and then allow access to the items with alternatives like:
var pb = $("#panelBar").data.("kendoPanelBar");
var item = pb.Items("myName");

or 

var item5 = pb.Items(5);

Further, make the expand. collapse, select methods become methods of the item so that....

$("#panelBar").Items("myItem").expand();

is the way it is done.

I am sure the same principle can be applied to other widgets like Menu, for example.