Imperial dimensions on metric drawing

Is there something i’m missing… I have a metric drawing, but I would like to have Imperial dimensions on a layout. I would like to do this without changing the drawing units. Is this possible?

The named dimension style definitions have an option for “Alternate” dimension that will let you do that, or you can make another named dimstyle with the primary setting adjusted to do what you want.
Have a look in Rhino Options - Document properties - Annotation