Motionmaker

I realize this is an old thread and you're on FCPX but I thought I'd chime in with one other insight: For Premiere users, Adobe Prelude will let you select certain clips from your AVCHD SD card and copy them to a new AVCHD folder with proper file structure (and will let you rename the project folder and MTS files accordingly!). I use this with my C100 for the same purpose as you're describing. I also sometimes shoot multiple projects in a day to the same card and want to archive them to separate AVCHD project folders. You can also transcode to multiple formats and destinations at the same time. I used to transcode everything to ProRes because I thought that was the only way to rename and organize my footage before learning this trick.