It would be both nice and informative if Rhino could support dotted linestype for isocurves while surface edges was solid curves. (I saw an image here of a boathull that was modelled in Catia I think, that had this, and it made the shape easy to read)
+1. It used to be possible via modifying DisplayModes ini file (not exposed to UI directly, pretty much any linetype definition, not transparency), but got broken in V6. Would be great to have it back, possibly with added UI.