VolumeWorks for Mac

From SubRosaSoft:

Resize and manage the partitions (volumes) on the hard drives on your Apple Macintosh computer without erasing them. VolumeWorks is extremely easy to use. In just a few clicks, VolumeWorks will resize your partition to the size of your choice. VolumeWorks will even defragment the disk if necessary to allow for shrinking. You can use VolumeWorks to create and delete partitions, with many custom icons that can be automatically applied to your newly created partition.

VolumeWorks can hide partitions from users as well. VolumeWorks also has the ability to shift a partition on the hard drive in addition to reconstructing partition maps. Version 1.5 may include unspecified updates, enhancements, or bug fixes.