gehenna: The problem being you can't boot off an internal drive connected to the CD SATA adapter. Only the original HDD bay SATA adapter is bootable.
If I recall correctly.
Also a Hybrid drive won't work correctly in Mac OS X unless you do some complicated and clever terminal hacking to turn it into a Fusion drive. Without doing that there is no way the OS can manage where to place the files to take advantage of the SSD aspect of the drive.
No problem booting from a SSD in my CD bay