We have many cards. This would make MC break out in an agitated sweat , but we actually download each card to it's own folder.  It's just the way we do it.  Recently, started having corrupt files.  It was easy to identify the card.  Each of our cards have a unique ID#.  If I could just trace the file back to it's originating card, and automate the task of downloading, and get away from so many subfolders, it would of course be huge for me.  The camera isn't an issue really since it's easy to see from the the file which camera captured.  Lightroom makes using subfolders a non-issue for us.  We are wedding and event photographers btw.  Our current folder structure is simply YYYYMMDD EVENT/RAW/cfcardid

I would love it if you had a simple space by each source folder that you could type in a card ID (or whatever).  Whatever was typed in that space would be added to the naming convention during import/renaming.  It would simply let me identify which card the file came from.  Let's me identify problem cards or cameras, etc.  That would be huge for my anal retentive soul.

Always a fan of your work

mike