I know they will not import directly, but is there a conversion program that can turn .csv files into .gpx files? I do road rallies and MS&T is going the way of the Dodo. Being able to use a spreadsheet to sort and list waypoints first is awesome, but can't find a way to do this in BaseCamp. I like Basecamp just fine, but this would make it better...!
I would recommend JaVaWa's RTWtool (Route, Waypoint, Track tool), it has an import wizard for CSV files, very handy. Export to GPX or GDB or clipboard and then paste results it into a BaseCamp list.