I have posted on this before - if you create a linestyle made of arcs you can then use any Line - or polygon using that linestyle to create these revision clouds - I have a linestyle for this - you have to however turn off Show all Lines as Solid in order to use it. It is easy to create a Linestyle in the linestyle editor. You can also use the Spline Property of Polylines if you want the line to be curvilinear - you can also spline Rectangles to give them curved corners.
Click Here for Link to other Post or search Revision Cloud and you will find it
Alan