yes you can.
just add your extra hdd after the installation, add it in fstab to mount it in your ibay's folder ( copy files on it before mounting it to the folder , if there is already some files in the ibay).
try not to mount to entire /home/e-smith nor /home/e-smith/files because a lot o configuration files are in this ... if your 2° hdd fails , then your SME won't be able to load correctly.
the best you can do is one folde rper ibay or user on your 2° SME or
one ibays folder mounted to /home/e-smith/files/ibays and one user folder mounted to /home/e-smith/files/users. Or you can do symlinks manually for each ibays and users and mount your drive to another place like /media/bigdrive/
Here is an how to on this site :
http://no.longer.valid/phpwiki/index.php/extra%20hard%20disktry to search on the forum and on the documentation, there's a lot of answer to many of your questions.