I frequently work with sheetmetal parts that have a large bend radius, but only a small angle of arc.  An example would be a 1/2 inch metal plate with a 450 inch inside radius and a 5 degree arc.  When I model it as a revolved feature I can flatten it, but SolidWorks sometimes alters the edges of the part.  When I try to create the bend from the flat, I keep getting a "This radius is too large" error message.  Any ideas on how to do this?