just curious if SSDs would be a viable replacement here?
I imagine cost will be the key issue in whether it's viable. Do you need 16-terabytes of storage, or did you just buy a lot of extra space? How much would the SSD replacements cost you? You said your current hard disc drive-based setup is noisy, but you didn't say it was too slow.
Even if you go for SSD's that aren't especially high data transfer rate (speaking of which, just how fast do you need your main storage (not the backup) to be?), what cost are you looking at?
From a little quick Googling, I take it your 2 Thunderbays can house either HDD or SSD, so in theory it's down to the cost of the SSDs. How many drives can each of your Thunderbays hold?
You mention 2 16-TB Thunderbay setups, of which one is the backup to the other, but say they are set on RAID 0, which has no redundancy in order to focus on higher speed. Maybe it's just me, but I found that a little confusing.