Anyone know if this would also work with an older laptop where you replace the optical drive with a HDD and put an SSD in the hard disk bay? That could breathe some life into my aging late 2008 Macbook 13".
Yes, see some of the other comments here mentioning the Optibay.
My old-school first-gen Unibody lasted me quite a while thanks to the MCE Optibay. I installed an SSD in place of the superdrive for the os/apps and a 320GB old school spinning drive for music/photos/etc...
That old Core 2 Duo felt faster than most modern computers purely because IO was so much faster.
I did this today on a 2010 MBP with a 250gb optibay drive. Nuked everything, ran the terminal commands from the Mountain Lion on usb stick, then installed mountain Lion. Installed and works great. Fast.
