app to manage symbolic links and move files automatically? I have about a terabyte of media files on an external hard drive. At any given moment I need a subset of these files locally on the SSD for faster access. Some times the hard drive isn't even available, but when it is I should still be able to use the files on it from a symlink path on the SSD. Is there an app that will automatically move groups of files back and forth, creating symlinks for the ones on the hard drive in the process?

I was able to find something like this for Windows: http://ozuke.comoj.com/ but have had no luck for OSX.  Would really like to find an existing solution before I start hacking away at python to make it myself.
IF you have a Mac that runs 10.8.3 AND has room for an extra internal drive. (Sacrifice the DVD on older MacBooks &amp; MacMinis)  A DIY "Fusion Drive" will accomplish your "goal".

http://blog.macsales.com/17624-os-x-10-8-3-provides-fusion-drive-setup-option-for-non-fusion-drive-equipped-macs

It is not a simple or strait-forward process however, 
Made DIY fusion drive.... now recovery partition won&#39;t boot