Double Ditto! This feature is needed so bad, but I don't think anyone at Garmin cares. I would be very interested to hear about the future software plans for the Garmin chart plotters.
There is no information on storing QuickDraw Contours on an SD card. I have downloaded multiple Quick Draw areas and named each of them for a specific lake I want to be on. But am not sure if my Echomap 73sv will read any other files names other than the one you download directly from the QuickDraw community. I haven't been able to try it yet because my boat has been put in storage all winter and I can't play with my unit indoors unless I buy another mount and power cable ($30-70$).