Sorry, the forums not having email notifications really sucks...wasn't ignoring :)
I would just use Sitefinity thunder to create a custom widget and use that. However if you want to use JUST the UI it should be possible I think.
So in the attached images you could add in your own datasource...perhaps just an old-school SqlDataSource. Once dropped onto the page you can edit it to set the properties, then drop on a RadGrid, and set it's datasource to the ID of the datasource control
...easiest thing though...use thunder and just wire it up in code, WAY more configurable. I like member listings to be in a Listview not grid format. So you cant really drag\drop the RadListView and configure it's templates in the sf page editor.