Give Tri-Backup 6 a look, it is what I have used to synchronize folders and volumes.
I would think you'd be on Snow Leopard ? by this point in t ime, for security if nothing else.
Systems: each to it s own disk drive or partition, but users can be anywhere, and general data also especially if shared and used by more than one person, or even if only one, outside the sysetm boot drive or individual user account home folder.
Maybe even stripe or JBOD some disk to have a single volume of data.
Maybe something else for searching?
And for size, location, of files and folders, and details, 3rd party there too.
To improve and enhance on the Finder I use to use Path Finder.