Vibration is hit or miss attribute, so it's highly unlikely that your drive would be a typical WD20EADS. It could be badly handled individual, or there may be different models of spindle used in that model, or just manufacturing variation between spindle motors.
This is just my guess, but I believe building a server with 2TB is better than using twice the number of 1TB drives. The fact that you got a bad unit once doesn't mean it's likely you get more of them. Vibration is really a hit-or-miss.
For example: my first 1TB 7200rpm Samsung F1 has very low vibration, on par or even less than my 1TB 5400rpm Greenpowers (both 1st and 2nd generation).
My second 1TB F1 is absolutely horrible. And my F2 Ecogreens are on par or better than my better F1 sample, thus way lower vibration than my Greenpowers.
So what doesn't add up? My Samsungs tend to have lower vibration than my WDs (which aren't bad either, just "not that special").. but that one sample just is absolutely horrible. There's no performance or reliability issue with it so far, just the vibration. It also happens to have a different colour spindle motor cap than all the other Samsungs in my posession, which probably means a different subcontractor for spindle motor, and a possible explanation. Samsung has had similar variation for ages. Back in P80 days, there was both NIDEC and JVC spindle motors. Nidec was quiter acoustically but may have vibrated more. JVC had a bad acoustic noise quality.
It may be "hit-or-miss" more so than idle whine due to the tolerances and speeds associated with a spinning platter, but in this case the increased vibration is most likely due to the extra weight associated with the 4th platter in the 2TB version. The previous EADS drives were all 3 platters: 1TB was 3x333GB and the 1.5TB was 3x500GB.
Extra weight = more weight in motion = more vibrational energy.
The extra weight also puts more load on the motor which would likely make it run hotter as well.
OP, I wouldn't worry about suspending 16 drives, you'll have a hard enough time fitting them all in any standard case, let alone keeping them cool. If it came down to it, you can get a case that has an all 5.25" front (like the Antec 1200), but you'd still have a hard time fitting 16 drives unless you were able to fit 4 - 4x3 drive enclosures. More than likely you'd have to go the rackmount server chasis route, or go with a 9U cube design (Lian-Li has one).
Beyond that, you'd be getting into some serious territory with storage, parity/redundancy, backups and etc, so I hope you know what you're doing.