I would like Progress Telerik to add a configuration option to the kendoButtonGroup widget called "layout". It would allow two possibilities -- "horizontal" (the default) or "vertical".
Thus, a developer could define a button group like this:
$('#buttonGroupId').kendoButtonGroup({
index: 0,
layout: "vertical"
});
Note: This would make the layout configuration consistent with the KendoRadioGroup as documented here: